[top]
000
FXUS62 KGSP 190215
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1015 PM EDT TUE JUN 18 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION ON WEDNESDAY...BUT
WITHOUT ENOUGH MOISTURE TO EXPECT MORE THAN ISOLATED SHOWERS. MOIST
EASTERLY FLOW WILL THEN KEEP SOME RAIN CHANCES THRU LATE WEEK MAINLY
OVER THE MOUNTAINS. HIGH PRESSURE WILL BUILD OVER THE AREA FOR THE
WEEKEND...MAINTAINING A WARM AND MOIST AIRMASS WITH A CHANCE OF
SHOWERS AND THUNDERSTORMS EACH AFTERNOON.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
930 PM UPDATE...DUE TO LARGELY BOUNDARY-PARALLEL SHEAR...CELLS THAT
INITIALLY FORMED AROUND SUNSET HAVE TRAINED ROUGHLY ALONG A
GREENVILLE TO CHESTER LINE IN CONVERGENT ZONE NEAR THE FRONT.
ACTIVITY NOW BEGINNING TO DIMINISH AS INSTABILITY WANES...BUT SOME
PRECIP LIKELY TO CONTINUE FOR ANOTHER HOUR OR SO AT LEAST. HOWEVER
WITH OUTFLOW PUSHING OUT ACRS GREENVILLE AND SPARTANBURG COUNTIES
CAN/T RULE OUT A COUPLE OF ISOLATED SHOWERS FIRING FROM THE SRN
PORTIONS OF THOSE COUNTIES SOUTH. NORTH OF THE CURRENT ACTIVITY
PRECIP CHANCES ARE TOO SMALL TO MENTION THIS EVENING. STORMS ALONG
THE UPSTREAM BOUNDARY OVER KY WOULD TAKE UNTIL AFTER MIDNIGHT TO
REACH THE TN/NC BORDER...BUT THEY ARE ALREADY STRUGGLING IN THE MORE
STABLE ENVIRONMENT THEY ARE ENTERING...SO DO NOT SEE A NEED TO
REFLECT THESE STORMS IN POPS TONIGHT. TEMPS HAVE BEEN ON TRACK SO
FAR THIS EVENING AND WILL MAINTAIN GOING LOWS.
730 PM UPDATE...PRECIP ACTIVITY NOW CONFINED TO THE PIEDMONT SHOULD
CONTINUE TO MOVE OUT OF THE CWFA WITH FRONT PUSHING INTO THAT AREA.
ACTIVITY GENERALLY WEAKENING WITH LOSS OF HEATING ANYWAY. RAP AS
WELL AS LOCAL WRF MODEL DO NOT SHOW ANY FURTHER DEVELOPMENT THIS
EVENING...AND WINDS ARE DRY AND DOWNSLOPING ANYWAY. STILL DO THINK
SOME OF THE REMAINING CU IN EAST TN AND THE MTNS OF WNC WILL REMAIN
AS PATCHY STRATUS FOR MUCH OF THE NIGHT...WITH CONVECTIVE DEBRIS
SPREADING ACROSS THE SE HALF OF THE CWFA TOO. KEPT PCLDY-MCLDY SKIES
OVERNIGHT AS A RESULT.
AS OF 230 PM EDT TUESDAY...A BIT OF A TRICKY FCST THIS AFTERNOON AND
EARLY EVENING. THE OVERALL PATTERN IS WELL AGREED UPON BY THE
MODELS...HOWEVER CONFIDENCE IN THE EVOLUTION OF S/W ENERGY ACROSS
THE CWFA IS NOT VERY HIGH DUE TO MODEL DIFFERENCES. THE LATEST RADAR
SHOWS AN UNSTABLE AIRMASS TO THE WEST BECOMING INCREASINGLY UNSTABLE
INTO THE WRN ZONES. VSBY SAY SHOW GOOD CLEARING AND HEATING TAKING
PLACE...BUT IN A DEEPLY MOIST ATMOS SBCAPE VALUES WILL LIKELY REACH
ONLY MOD LEVELS. THIS IS A LITTLE EVIDENT IN THE LOW TOP CONV SEEN
TO THE WEST. IN ANY REGARD...WILL ANTICIPATE TSTMS DEVELOPING AHEAD
OF THE WEAK COLD FRONT AND DEPENDING ON THE STRENGTH OF THE CROSS
S/W ENERGY...SOME OF THESE COULD BECOME STRONG TO SEVERE THIS
AFTERNOON. THE MAIN THREAT WOULD BE LARGE HAIL AND PERHAPS DAMAGING
WINDS AS DRIER AIR WORKS INTO THE MLVLS. EXPECT A WIND SHIFT ACROSS
THE MTNS AROUND 00Z AND INTO THE UPSTATE NEAR 05Z. THIS WILL
SUPPRESS ANY ACTIVITY TO THE SOUTH WITH A LOWER THETA/E AIRMASS
MIXING IN. SOME PATCHY DENSE FG IS POSSIBLE AROUND DAYBREAK IN THE
MTN VALLEYS AS THE PGRAD IS NOT REAL TIGHT BEHIND THE FRONT AND
BROADENS THROUGH 12Z.
A CP HIGH WILL WORK SOUTH INTO THE OH VALLEY TOMORROW AND PUSH A
BACKDOOR COLD FRONT INTO THE NRN ZONES BY THE AFTERNOON. THERE IS
NOT MUCH MOISTURE AVAILABLE WITH THIS SYSTEM SO WILL EXPECT THE BEST
PRECIP CHANCES ACROSS THE MTNS...WHERE AN E/LY UPSLOPE FLOW BRINGS
IN ATL MOISTURE. POPS HAVE BEEN HELD TO SLIGHT/CHANCE ACROSS THE
MTNS AND SLIGHT ELSEWHERE...WITH MAINLY -SHRA AND PERHAPS A MODERATE
THUNDERSTORM OR TWO ACROSS THE FHILLS AND MTNS. MAX TEMPS SHOULD
STILL BE A COUPLE DEGREES BELOW NORMAL WITH THE NE/LY SFC FLOW AND
AIRMASS MIXING.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 200 PM EDT TUESDAY...THE SHORT TERM WILL BE DOMINATED BY
SURFACE HIGH PRESSURE THAT WILL SET UP CAMP OFF THE NEW ENGLAND
COAST WHICH WILL REMAIN RIDGED SWD INTO THE SOUTHERN APPALACHIANS
THROUGH FRI. THE UPPER AIR PATTERN WILL BE ALMOST INDETERMINATE IN
THE DEEP SOUTH WITH VERY WEAK FLOW. THE AREA WILL BE BETWEEN A
TROUGH WELL TO THE NE AND AN UPPER RIDGE OVER THE SOUTHERN PLAINS.
HENCE...NO SIGNIFCANT UPPER FORCING IS ANTICIPATED. MODEL TIME
HEIGHTS INDICATE THAT MOISTURE WILL REMAIN RELATIVELY HIGH IN THE
BOUNDARY LAYER WITH DRYING ESSENTAILLY ABOVE 10KFT THROUGH THU NIGHT.
HOWEVER...MOISTURE IN THE COLUMN IS FORECAST TO DECREASE ON FRI.
HENCE...THE WEATHER SHOULD BE DRIVEN BY MAINLY BY THE LOW LEVEL WIND
FLOW AND ANY MECHANICAL LIFT IT MUSTERS...PLUS DIURNAL HEATING.
THEREFORE...MAINLY DIURNAL/SCATTERED CONVECTION IS EXPECTED PRIMARILY
OVER THE MOUNTAINS...WITH PERHAPS A DOWN TICK IN COVERAGE ON FRI
AFTERNOON DUE TO THE DRYER AIR. WITH THE WEAK UPSLOPE FLOW...SOME
NOCTURNAL WIDELY SCATTERED SHOWERS WILL REMAIN POSSIBLE OVER THE
MOUNTAINS WED/THU NIGHTS. USED AN ALLBLEND APPROACH TO TEMPERATURES
WHICH PRODUCED MAX TEMPS ON THU AND FRI ABOUT A CATEGORY BELOW
AVERAGE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 2 PM TUESDAY...THE MAIN FEATURE FOR THE EXTENDED PERIOD IS A
RIDGE OF HIGH PRESSURE THAT WILL SET UP OVER THE SOUTHEASTERN CONUS
OVER THE WEEKEND AND INTO MONDAY. THE BERMUDA HIGH WILL REMAIN
SITUATED OVER THE ATLANTIC OFF THE EAST COAST...SETTING UP A MOIST
SOUTHEASTERLY TO SOUTHWESTERLY LOW-LEVEL FLOW REGIME FOR THE REGION.
THIS WILL DRIVE MAINLY DIURNAL CONVECTION FOR THE PERIOD...WITH
GREATER CHANCE POPS FAVORING THE HIGHER ELEVATIONS EACH AFTERNOON
THROUGH THE MIDDLE OF NEXT WEEK. THE PERSISTENT RIDGE WILL ALLOW FOR
A SLIGHT WARMING TREND...WITH TEMPS NEAR TO SLIGHTLY ABOVE AVERAGE
BY THE END OF THE EXTENDED PERIOD.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...WINDS WILL SHIFT TO NW QUADRANT THIS EVENING AS FRONTAL
BOUNDARY ARRIVES...BUT TIMING TOUGH WITH TSTM ACTIVITY ACRS THE
REGION. HAVE SETTLED ON 03Z BASED MAINLY ON GFS MOS AND NAM. SOME
SHOWERS PRIOR TO THIS TIME AS WELL THOUGH VSBY SHUD REMAIN VFR.
DRIER AIR WILL WORK IN TONIGHT BUT SOME CLOUD COVER WILL LIKELY
REMAIN GIVEN AMT OF CONVECTIVE DEBRIS AT THIS TIME JUST BEFORE
SUNSET. DOWNSLOPING ON THE NW WINDS WILL LIMIT CLOUD DEVELOPMENT AND
GUIDANCE IN DECENT AGREEMENT THAT BKN CIG WILL REMAIN VFR. THIS WILL
MIX UP TO 050-060 WED MRNG. ISOLATED -SHRA AROUND THE AREA TMRW BUT
NOT WORTHY OF A TAF MENTION. LIGHT NLY WINDS FOLLOWING SHIFT.
ELSEWHERE...SHOWER/THUNDER CHANCES VERY SMALL AT TAF SITES THIS
EVENING AS DRIER...MORE STABLE AIR PUSHES IN BEHIND A COLD FRONT.
SITES THAT HAVE NOT ALREADY SEEN SHIFT TO NW WILL SEE IT BY EARLY
WED MRNG. LEFTOVER LOW CU OVER THE MTNS MAY CONGEAL INTO A MORE
SOLID DECK THIS EVENING BUT WITH THE DRY AND DOWNSLOPING FLOW CIGS
UNLIKELY TO LOWER MUCH...SO KEPT VFR CIGS AT ALL SITES. FAIRLY
STRONG SIGNAL FROM GUIDANCE THAT SOME FOG WILL FORM IN THE
MTNS/FOOTHILLS. WENT PREVAILING MVFR WITH TEMPO IFR AT KAVL/KHKY.
MIDLEVEL CIGS EXPECTED TOMORROW WITH ENUF CU DEVELOPMENT TO EXPECT
SOME ISOLATED SHOWERS...BUT WITH COVERAGE TOO LOW TO INCLUDE IN TAFS.
OUTLOOK...MOIST EASTERLY FLOW WILL SET UP WED NIGHT LEADING TO LOW
STRATUS ACROSS MUCH OF THE AREA THU MORNING WITH RESTRICTIONS LIKELY.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 72% HIGH 86% HIGH 100% HIGH 100%
KHKY HIGH 95% HIGH 91% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 95% HIGH 100% HIGH 100%
KAND HIGH 95% MED 72% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...VISIN
AVIATION...WIMBERLEY
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000
FXUS62 KCAE 190207
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1007 PM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SURFACE COLD FRONT IN THE UPSTATE ACROSS NORTHERN MIDLANDS AT
02Z. SHOWERS ALONG FRONTAL BOUNDARY...WITH LITTLE MOVEMENT TO THE
EAST/SOUTHEAST. OTHER SHOWERS AROUND COLUMBIA SHOW CONTINUED
WEAKENING TREND. COLD FRONT WILL BE MOVING SLOWLY SOUTH AND EAST
OVERNIGHT. INSTABILITY WILL BE WEAK OVERNIGHT AND FORCING LIMITED
TO WEAK CONVERGENCE ALONG FRONTAL BOUNDARY. SO ISOLATED TO
SCATTERED SHOWERS/THUNDERSTORMS AFTER MIDNIGHT.
WITH CLOUDS PERSISTING OVERNIGHT EXPECT LOW TEMPERATURES AROUND
70.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
UPPER TROUGH OVER THE REGION WEDNESDAY MOVES EAST BY THURSDAY AS
UPPER RIDGE STRENGTHENS OUT WEST BY THURSDAY NIGHT. SHORT WAVE DRAGS
A WEAK COLD FRONT THROUGH THE REGION WEDNESDAY. THE FRONT MOVES TO
THE SOUTH WEDNESDAY NIGHT AND ANOTHER QUITE WEAK SHORT WAVE DROPS
SOUTHWARD THURSDAY AND THURSDAY NIGHT. PLAN ON A 20-30 PERCENT CHANCE
OF SHOWERS AND THUNDERSTORMS WEDNESDAY AND A 20 PERCENT CHANCE
THURSDAY. EXPECT DIURNAL MAINLY LATE AFTERNOON AND EARLY EVENING
CONVECTIVE ACTIVITY. ALTHOUGH CAE AREA NOT OUTLOOKED FOR SEVERE
STORMS WEDNESDAY AFTERNOON...AFTERNOON SURFACE HEATING WITH TEMPERATURES
IN THE UPPER 80S TO NEAR 90 COULD CAUSE STEEPENING LAPSE RATES AND
CAUSE A FEW STRONG THUNDERSTORMS TO DEVELOP. ATMOSPHERE IS A
LITTLE DRIER WITH PWAT VALUES DOWN FROM 2.0 INCHES TODAY TO ABOUT
1.5 INCHES ON WEDNESDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT AS EAST COAST UPPER TROUGH
FRIDAY EXITS TO THE EAST AND UPPER RIDGE BUILDS ACROSS THE REGION
SATURDAY THROUGH TUESDAY. WITH UPPER RIDGE IN THE VICINITY...
TEMPERATURES SHOULD ON THE RISE. HIGHS UPPER 80S FRIDAY WILL
INCREASE TO THE LOWER 90S BY MONDAY AND TUESDAY. OVERNIGHT LOWS
ARE EXPECTED TO BE IN THE UPPER 60S TO AROUND 70. MAINLY DIURNAL
CONVECTIVE ACTIVITY DURING THE PERIOD AS EXPECT A SLIGHT CHANCE
OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. SO...FAIRLY
TYPICAL SUMMER-LIKE CONDITIONS AS THE SUMMER SOLSTICE APPROACHES.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR AT THE TERMINALS CURRENTLY. RADAR INDICATES WEAKENING SHOWER
ACTIVITY NEAR CAE/CUB...AND A FEW SHOWERS AND THUNDERSTORMS WELL TO
THE NORTH OF THE TERMINALS. ONCE CONVECTION ASSOCIATED WITH A
FRONTAL BOUNDARY DISSIPATES LATER TONIGHT...FOCUS WILL SHIFT TO ANY
FOG/STRATUS THREAT FOR LATE TONIGHT/EARLY WED. LATEST GUIDANCE
GENERALLY POINTING TO POSSIBILITIES OF MVFR CONDITIONS.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR WEDNESDAY. SOME DRIER
AIR WILL ENTER OUR FORECAST AREA BEHIND THE FRONT...WITH CHANCES
OF CONVECTION WEDNESDAY MAINLY TO OUR SOUTH. CHANCES TOO LOW TO
INCLUDE MENTION IN TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...SLIGHT CHANCE OF MAINLY
AFTERNOON/EVENING THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
[top]
000
FXUS62 KCHS 190152
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
952 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT...THEN
SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH
PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND
SETTLE OVER THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AN EXPANSIVE UPPER LEVEL TROUGH WILL REMAIN IN PLACE OVER THE
EASTERN STATES TONIGHT. MEANWHILE AT THE SURFACE...A COLD FRONT
EXTENDS FROM LOW PRESSURE ALONG THE MID-ATLANTIC COAST SOUTHWEST
THROUGH THE PIEDMONT OF NORTH CAROLINA...THE UPSTATE OF SOUTH
CAROLINA AND INTO NORTHERN GEORGIA LATE THIS EVENING. AS THE LOW
SHIFTS OFF THE MID-ATLANTIC COAST LATER TONIGHT...THE FRONT WILL
SLOWLY DROP TOWARD THE AREA BUT BECOME MORE WEST-EAST ORIENTED AND
SLOW AS IT BECOMES NEARLY PARALLEL TO THE FLOW ALOFT.
WEAKENING UPSTREAM CONVECTION OUT AHEAD OF THE COLD FRONT WILL
CONTINUE TO PROGRESS TOWARD THE AREA LATE THIS EVENING...AND
EXPECT SOME OF IT TO HOLD TOGETHER AS IT SHIFTS INTO THE AREA
AFTER ABOUT 11 PM WITH SUPPORT OF A MID-LEVEL IMPULSE APPROACHING
FROM THE WEST. WILL THEREFORE KEEP A SLIGHT CHANCE OR CHANCE OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST TONIGHT. WHILE A STRONG
OR SEVERE THUNDERSTORM IS POSSIBLE...THE ATMOSPHERE SHOULD
STABILIZE SOME WITH THE LOSS OF DIURNAL HEATING.
THE TEMPERATURE CURVE WILL SHOW SLOWLY FALLING TEMPERATURES...BEFORE
LATE NIGHT HEAT LOSS IS MAXIMIZED AND LOWS REACH THE LOWER AND
MIDDLE 70S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY AND THURSDAY...A COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA BY WEDNESDAY MORNING
BEFORE GRADUALLY STALLING SOUTH OF THE REGION BY THURSDAY. AS THIS
OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL FORCING FROM AN H5
SHORTWAVE SHOULD FAVOR PERIODS OF SHOWERS/THUNDERSTORMS THROUGH MUCH
OF WEDNESDAY...ESPECIALLY ALONG/NEAR THE PASSING COLD FRONT. HAVE
THEREFORE INCREASED POPS TO 50-60 WEDNESDAY AFTERNOON MAINLY ALONG
COASTAL LOCATIONS IN SOUTHEAST GEORGIA CLOSER TO THE FRONT. AT THIS
TIME...CLOUD COVER WILL REMAIN A LIMITING FACTOR FOR STRONGER
THUNDERSTORMS TO DEVELOP OVER THE REGION. HOWEVER...WEAK WIND FIELDS
WILL LIKELY RESULT IN SLOW STORM MOTIONS THAT MAY CONTRIBUTE TO
HEAVY RAINFALL DURING A FEW THUNDERSTORMS.
A GRADUAL DECREASE IN OVERALL POPS SHOULD THEN OCCUR FROM NORTH TO
SOUTH WEDNESDAY NIGHT INTO THURSDAY AS THE FRONT SLOWLY SLIPS TO THE
SOUTH OF THE FORECAST AREA...BUT HAVE MAINTAINED A MENTION OF PRECIP
OVER ALL LOCATIONS THROUGH THURSDAY NIGHT...WITH 20 POPS OVER INLAND
SOUTH CAROLINA TO 30-40 POPS OVER LOCATIONS SOUTH OF INTERSTATE 16
IN GEORGIA. OVERALL HIGH TEMPS ARE EXPECTED TO PEAK IN THE MID/UPPER
80S OVER MOST LOCATIONS WEDNESDAY AND THURSDAY...WITH SLIGHTLY COOLER
TEMPS IN THE MID 80S OVER SOUTH CAROLINA BEHIND THE FRONT. OVERNIGHT
LOWS ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FRIDAY...SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
NORTH...WITH THE PATTERN EVENTUALLY TRANSITIONING INTO AN INLAND
WEDGE/COASTAL TROUGH TYPE SCENARIO. A FEW MODELS INDICATE A WEAK
WAVE/SFC LOW DEVELOPING ALONG THE STALLED FRONT JUST OFFSHORE LATE
MORNING/EARLY AFTERNOON BEFORE DRIFTING ONSHORE DURING THE EVENING.
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND/OR THUNDERSTORMS WILL
THEREFORE BE MAINTAINED IN THE CURRENT FORECAST...WITH HIGHEST
CHANCES OVER SOUTHEAST GEORGIA COUNTIES. OVERALL HIGH TEMPS SHOULD
REMAIN IN THE MID/UPPER 80S WITH SLIGHTLY COOLER TEMPS ALONG COASTAL
COUNTIES AND THE TRI COUNTY AREA DUE TO ENHANCED CLOUD COVER AND
HIGH PRESSURE NUDGING IN FROM THE NORTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL THROUGH 00Z
THURSDAY. THERE COULD BE SOME MVFR CEILINGS WEDNESDAY
MORNING...BUT THERE IS NOT ENOUGH CONFIDENCE TO INCLUDE MENTION IN
THE FORECAST AT THIS TIME. THE PROXIMITY OF A FRONT WILL RESULT IN
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FROM MIDDAY
WEDNESDAY THROUGH THE EARLY EVENING AND HAVE VICINITY
THUNDERSTORMS IN THE FORECAST AT BOTH TERMINALS STARTING AT 16Z.
EXTENDED AVIATION...MVFR CIGS/VSBYS POSSIBLE THROUGH THURSDAY DUE
TO SHOWERS AND/OR THUNDERSTORMS. LOW CHANCE OF MVFR CIGS/VSBYS
FRIDAY AFTERNOON/EVENING WITH A COASTAL TROUGH/SFC LOW SHIFTING
ONSHORE.
&&
.MARINE...
TONIGHT...THE PRESSURE GRADIENT IS CONTINUING TO TIGHTEN BETWEEN
THE STRONG SUB-TROPICAL ATLANTIC RIDGE TO THE SE AND AN UPSTREAM
COLD FRONT TO THE NW. THE PACKING OF THE ISOBARS WILL BECOME
GREATEST EARLY TONIGHT BETWEEN THE COLD FRONT AND ATLANTIC
HIGH...AS GEOSTROPHIC WINDS CLIMB TO 25-30 KT. THIS IS SUPPORTIVE
OF A MARGINAL SCA ACROSS OUR OUTER GA WATERS FOR SOME 5-6 FOOTERS
AND FREQUENT GUSTS OF 25 KT. THE OTHER WATERS LOOK TO REMAIN JUST
BELOW ANY HEADLINE CONDITIONS...WITH WINDS PEAKING AT 15 OR 20 KT
AND SEAS AT 3-5 FT.
WEDNESDAY THROUGH SATURDAY...WINDS/SEAS ARE EXPECTED TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA AS A COLD FRONT SHIFTS OVER THE
COASTAL WATERS WEDNESDAY BEFORE STALLING NEAR/OVER SOUTHERN GA
WATERS ON THURSDAY. AS THE FRONT SLOWLY SHIFTS SOUTH...SOUTHERLY
WINDS WILL VEER BEHIND THE FRONT AND EVENTUALLY BECOME
NORTHEAST/EAST THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE
NORTH OVER THE WATERS INTO EARLY FRIDAY...WITH WIND SPEEDS
APPROACHING 15-20 KTS OVER NORTHERN SC WATERS AND SEAS BUILDING TO
3-4 FT. ENHANCED EAST/NORTHEAST FLOW MAY CONTINUE INTO SATURDAY
AS A COASTAL TROUGH DEVELOPS OFFSHORE AND GRADUALLY SHIFTS OVER
LAND.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...DPB
LONG TERM...
AVIATION...JAQ
MARINE...JAQ/DPB
000
FXUS62 KCHS 190127
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
927 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT...THEN
SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH
PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND
SETTLE OVER THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AN EXPANSIVE UPPER LEVEL TROUGH WILL REMAIN IN PLACE OVER THE
EASTERN STATES TONIGHT. MEANWHILE AT THE SURFACE...A COLD FRONT
EXTENDS FROM LOW PRESSURE ALONG THE MID-ATLANTIC COAST SOUTHWEST
THROUGH THE PIEDMONT OF NORTH CAROLINA...THE UPSTATE OF SOUTH
CAROLINA AND INTO NORTHERN GEORGIA LATE THIS EVENING. AS THE LOW
SHIFTS OFF THE MID-ATLANTIC COAST LATER TONIGHT...THE FRONT WILL
SLOWLY DROP TOWARD THE AREA BUT BECOME MORE WEST-EAST ORIENTED AND
SLOW AS IT BECOMES NEARLY PARALLEL TO THE FLOW ALOFT.
WEAKENING UPSTREAM CONVECTION OUT AHEAD OF THE COLD FRONT WILL
CONTINUE TO PROGRESS TOWARD THE AREA LATE THIS EVENING...AND
EXPECT SOME OF IT TO HOLD TOGETHER AS IT SHIFTS INTO THE AREA
AFTER ABOUT 11 PM WITH SUPPORT OF A MID-LEVEL IMPULSE APPROACHING
FROM THE WEST. WILL THEREFORE KEEP A SLIGHT CHANCE OR CHANCE OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST TONIGHT. WHILE A STRONG
OR SEVERE THUNDERSTORM IS POSSIBLE...THE ATMOSPHERE SHOULD
STABILIZE SOME WITH THE LOSS OF DIURNAL HEATING.
THE TEMPERATURE CURVE WILL SHOW SLOWLY FALLING TEMPERATURES...BEFORE
LATE NIGHT HEAT LOSS IS MAXIMIZED AND LOWS REACH THE LOWER AND
MIDDLE 70S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY AND THURSDAY...A COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA BY WEDNESDAY MORNING
BEFORE GRADUALLY STALLING SOUTH OF THE REGION BY THURSDAY. AS THIS
OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL FORCING FROM AN H5
SHORTWAVE SHOULD FAVOR PERIODS OF SHOWERS/THUNDERSTORMS THROUGH MUCH
OF WEDNESDAY...ESPECIALLY ALONG/NEAR THE PASSING COLD FRONT. HAVE
THEREFORE INCREASED POPS TO 50-60 WEDNESDAY AFTERNOON MAINLY ALONG
COASTAL LOCATIONS IN SOUTHEAST GEORGIA CLOSER TO THE FRONT. AT THIS
TIME...CLOUD COVER WILL REMAIN A LIMITING FACTOR FOR STRONGER
THUNDERSTORMS TO DEVELOP OVER THE REGION. HOWEVER...WEAK WIND FIELDS
WILL LIKELY RESULT IN SLOW STORM MOTIONS THAT MAY CONTRIBUTE TO
HEAVY RAINFALL DURING A FEW THUNDERSTORMS.
A GRADUAL DECREASE IN OVERALL POPS SHOULD THEN OCCUR FROM NORTH TO
SOUTH WEDNESDAY NIGHT INTO THURSDAY AS THE FRONT SLOWLY SLIPS TO THE
SOUTH OF THE FORECAST AREA...BUT HAVE MAINTAINED A MENTION OF PRECIP
OVER ALL LOCATIONS THROUGH THURSDAY NIGHT...WITH 20 POPS OVER INLAND
SOUTH CAROLINA TO 30-40 POPS OVER LOCATIONS SOUTH OF INTERSTATE 16
IN GEORGIA. OVERALL HIGH TEMPS ARE EXPECTED TO PEAK IN THE MID/UPPER
80S OVER MOST LOCATIONS WEDNESDAY AND THURSDAY...WITH SLIGHTLY COOLER
TEMPS IN THE MID 80S OVER SOUTH CAROLINA BEHIND THE FRONT. OVERNIGHT
LOWS ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FRIDAY...SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
NORTH...WITH THE PATTERN EVENTUALLY TRANSITIONING INTO AN INLAND
WEDGE/COASTAL TROUGH TYPE SCENARIO. A FEW MODELS INDICATE A WEAK
WAVE/SFC LOW DEVELOPING ALONG THE STALLED FRONT JUST OFFSHORE LATE
MORNING/EARLY AFTERNOON BEFORE DRIFTING ONSHORE DURING THE EVENING.
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND/OR THUNDERSTORMS WILL
THEREFORE BE MAINTAINED IN THE CURRENT FORECAST...WITH HIGHEST
CHANCES OVER SOUTHEAST GEORGIA COUNTIES. OVERALL HIGH TEMPS SHOULD
REMAIN IN THE MID/UPPER 80S WITH SLIGHTLY COOLER TEMPS ALONG COASTAL
COUNTIES AND THE TRI COUNTY AREA DUE TO ENHANCED CLOUD COVER AND
HIGH PRESSURE NUDGING IN FROM THE NORTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL THROUGH 00Z
THURSDAY. TIMING UPSTREAM CONVECTION...THUNDERSTORMS HAVE BEEN ADDED TO THE
FORECAST IN A TEMPO GROUP FROM 03-06Z AT KCHS AND 04-07Z AT KSAV.
THERE COULD BE SOME MVFR CEILINGS WEDNESDAY MORNING...BUT THERE IS
NOT ENOUGH CONFIDENCE TO INCLUDE MENTION IN THE FORECAST AT THIS
TIME. THE PROXIMITY OF A FRONT WILL RESULT IN SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS FROM MIDDAY WEDNESDAY THROUGH
THE EARLY EVENING AND HAVE VICINITY THUNDERSTORMS IN THE FORECAST
AT BOTH TERMINALS STARTING AT 16Z.
EXTENDED AVIATION...MVFR CIGS/VSBYS POSSIBLE THROUGH THURSDAY DUE
TO SHOWERS AND/OR THUNDERSTORMS. LOW CHANCE OF MVFR CIGS/VSBYS
FRIDAY AFTERNOON/EVENING WITH A COASTAL TROUGH/SFC LOW SHIFTING
ONSHORE.
&&
.MARINE...
TONIGHT...THE PRESSURE GRADIENT IS CONTINUING TO TIGHTEN BETWEEN
THE STRONG SUB-TROPICAL ATLANTIC RIDGE TO THE SE AND AN UPSTREAM
COLD FRONT TO THE NW. THE PACKING OF THE ISOBARS WILL BECOME
GREATEST EARLY TONIGHT BETWEEN THE COLD FRONT AND ATLANTIC
HIGH...AS GEOSTROPHIC WINDS CLIMB TO 25-30 KT. THIS IS SUPPORTIVE
OF A MARGINAL SCA ACROSS OUR OUTER GA WATERS FOR SOME 5-6 FOOTERS
AND FREQUENT GUSTS OF 25 KT. THE OTHER WATERS LOOK TO REMAIN JUST
BELOW ANY HEADLINE CONDITIONS...WITH WINDS PEAKING AT 15 OR 20 KT
AND SEAS AT 3-5 FT.
WEDNESDAY THROUGH SATURDAY...WINDS/SEAS ARE EXPECTED TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA AS A COLD FRONT SHIFTS OVER THE
COASTAL WATERS WEDNESDAY BEFORE STALLING NEAR/OVER SOUTHERN GA
WATERS ON THURSDAY. AS THE FRONT SLOWLY SHIFTS SOUTH...SOUTHERLY
WINDS WILL VEER BEHIND THE FRONT AND EVENTUALLY BECOME
NORTHEAST/EAST THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE
NORTH OVER THE WATERS INTO EARLY FRIDAY...WITH WIND SPEEDS
APPROACHING 15-20 KTS OVER NORTHERN SC WATERS AND SEAS BUILDING TO
3-4 FT. ENHANCED EAST/NORTHEAST FLOW MAY CONTINUE INTO SATURDAY
AS A COASTAL TROUGH DEVELOPS OFFSHORE AND GRADUALLY SHIFTS OVER LAND.
RIP CURRENTS...WE HAVE MAINTAINED A MODERATE RISK AT THE BEACHES
THROUGH THIS EVENING...DUE TO SOUTH AND SW WINDS AT 15 TO 20 MPH
AND A 2 FOOT SWELL EVERY 10 SECONDS. THE RISK FOR TOMORROW HOWEVER
IS LOW WITH MUCH LESS WIND.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...DPB
LONG TERM...
AVIATION...JAQ
MARINE...JAQ/DPB
000
FXUS62 KCHS 190032
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
832 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT...THEN
SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH
PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND
SETTLE OVER THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AN EXPANSIVE UPPER LEVEL TROUGH WILL REMAIN IN PLACE OVER THE
EASTERN STATES TONIGHT. MEANWHILE AT THE SURFACE...A COLD FRONT
EXTENDS FROM LOW PRESSURE ALONG THE MID-ATLANTIC COAST SOUTHWEST
THROUGH THE PIEDMONT OF NORTH CAROLINA...THE UPSTATE OF SOUTH
CAROLINA AND INTO NORTHERN GEORGIA THIS EVENING. AS THE LOW SHIFTS
OFF THE MID-ATLANTIC COAST LATER TONIGHT...THE FRONT WILL SLOWLY
DROP TOWARD THE AREA BUT BECOME MORE WEST-EAST ORIENTED AND SLOW
AS IT BECOMES NEARLY PARALLEL TO THE FLOW ALOFT.
UPSTREAM CONVECTION OUT AHEAD OF THE COLD FRONT WILL CONTINUE TO
PROGRESS TOWARD THE AREA THIS EVENING...AND EXPECT MUCH OF IT TO
HOLD TOGETHER AS IT SHIFTS INTO THE AREA DURING THE LATE EVENING
AND OVERNIGHT HOURS WITH SUPPORT OF A MID-LEVEL IMPULSE
APPROACHING FROM THE WEST. WILL THEREFORE KEEP A CHANCE OF SHOWERS
AND THUNDERSTORMS IN THE FORECAST TONIGHT. WHILE A STRONG OR
SEVERE THUNDERSTORM IS POSSIBLE...THE ATMOSPHERE SHOULD STABILIZE
SOME WITH THE LOSS OF DIURNAL HEATING.
THE TEMPERATURE CURVE WILL SHOW SLOWLY FALLING TEMPERATURES...BEFORE
LATE NIGHT HEAT LOSS IS MAXIMIZED AND LOWS REACH THE LOWER AND
MIDDLE 70S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY AND THURSDAY...A COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA BY WEDNESDAY MORNING
BEFORE GRADUALLY STALLING SOUTH OF THE REGION BY THURSDAY. AS THIS
OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL FORCING FROM AN H5
SHORTWAVE SHOULD FAVOR PERIODS OF SHOWERS/THUNDERSTORMS THROUGH MUCH
OF WEDNESDAY...ESPECIALLY ALONG/NEAR THE PASSING COLD FRONT. HAVE
THEREFORE INCREASED POPS TO 50-60 WEDNESDAY AFTERNOON MAINLY ALONG
COASTAL LOCATIONS IN SOUTHEAST GEORGIA CLOSER TO THE FRONT. AT THIS
TIME...CLOUD COVER WILL REMAIN A LIMITING FACTOR FOR STRONGER
THUNDERSTORMS TO DEVELOP OVER THE REGION. HOWEVER...WEAK WIND FIELDS
WILL LIKELY RESULT IN SLOW STORM MOTIONS THAT MAY CONTRIBUTE TO
HEAVY RAINFALL DURING A FEW THUNDERSTORMS.
A GRADUAL DECREASE IN OVERALL POPS SHOULD THEN OCCUR FROM NORTH TO
SOUTH WEDNESDAY NIGHT INTO THURSDAY AS THE FRONT SLOWLY SLIPS TO THE
SOUTH OF THE FORECAST AREA...BUT HAVE MAINTAINED A MENTION OF PRECIP
OVER ALL LOCATIONS THROUGH THURSDAY NIGHT...WITH 20 POPS OVER INLAND
SOUTH CAROLINA TO 30-40 POPS OVER LOCATIONS SOUTH OF INTERSTATE 16
IN GEORGIA. OVERALL HIGH TEMPS ARE EXPECTED TO PEAK IN THE MID/UPPER
80S OVER MOST LOCATIONS WEDNESDAY AND THURSDAY...WITH SLIGHTLY COOLER
TEMPS IN THE MID 80S OVER SOUTH CAROLINA BEHIND THE FRONT. OVERNIGHT
LOWS ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FRIDAY...SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
NORTH...WITH THE PATTERN EVENTUALLY TRANSITIONING INTO AN INLAND
WEDGE/COASTAL TROUGH TYPE SCENARIO. A FEW MODELS INDICATE A WEAK
WAVE/SFC LOW DEVELOPING ALONG THE STALLED FRONT JUST OFFSHORE LATE
MORNING/EARLY AFTERNOON BEFORE DRIFTING ONSHORE DURING THE EVENING.
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND/OR THUNDERSTORMS WILL
THEREFORE BE MAINTAINED IN THE CURRENT FORECAST...WITH HIGHEST
CHANCES OVER SOUTHEAST GEORGIA COUNTIES. OVERALL HIGH TEMPS SHOULD
REMAIN IN THE MID/UPPER 80S WITH SLIGHTLY COOLER TEMPS ALONG COASTAL
COUNTIES AND THE TRI COUNTY AREA DUE TO ENHANCED CLOUD COVER AND
HIGH PRESSURE NUDGING IN FROM THE NORTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL THROUGH 00Z
THURSDAY. TIMING UPSTREAM CONVECTION...THUNDERSTORMS HAVE BEEN ADDED TO THE
FORECAST IN A TEMPO GROUP FROM 03-06Z AT KCHS AND 04-07Z AT KSAV.
THERE COULD BE SOME MVFR CEILINGS WEDNESDAY MORNING...BUT THERE IS
NOT ENOUGH CONFIDENCE TO INCLUDE MENTION IN THE FORECAST AT THIS
TIME. THE PROXIMITY OF A FRONT WILL RESULT IN SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS FROM MIDDAY WEDNESDAY THROUGH
THE EARLY EVENING AND HAVE VICINITY THUNDERSTORMS IN THE FORECAST
AT BOTH TERMINALS STARTING AT 16Z.
EXTENDED AVIATION...MVFR CIGS/VSBYS POSSIBLE THROUGH THURSDAY DUE
TO SHOWERS AND/OR THUNDERSTORMS. LOW CHANCE OF MVFR CIGS/VSBYS
FRIDAY AFTERNOON/EVENING WITH A COASTAL TROUGH/SFC LOW SHIFTING
ONSHORE.
&&
.MARINE...
TONIGHT...THE PRESSURE GRADIENT IS CONTINUING TO TIGHTEN BETWEEN
THE STRONG SUB-TROPICAL ATLANTIC RIDGE TO THE SE AND AN UPSTREAM
COLD FRONT TO THE NW. THE PACKING OF THE ISOBARS WILL BECOME
GREATEST EARLY TONIGHT BETWEEN THE COLD FRONT AND ATLANTIC
HIGH...AS GEOSTROPHIC WINDS CLIMB TO 25-30 KT. THIS IS SUPPORTIVE
OF A MARGINAL SCA ACROSS OUR OUTER GA WATERS FOR SOME 5-6 FOOTERS
AND FREQUENT GUSTS OF 25 KT. THE OTHER WATERS LOOK TO REMAIN JUST
BELOW ANY HEADLINE CONDITIONS...WITH WINDS PEAKING AT 15 OR 20 KT
AND SEAS AT 3-5 FT.
WEDNESDAY THROUGH SATURDAY...WINDS/SEAS ARE EXPECTED TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA AS A COLD FRONT SHIFTS OVER THE
COASTAL WATERS WEDNESDAY BEFORE STALLING NEAR/OVER SOUTHERN GA
WATERS ON THURSDAY. AS THE FRONT SLOWLY SHIFTS SOUTH...SOUTHERLY
WINDS WILL VEER BEHIND THE FRONT AND EVENTUALLY BECOME
NORTHEAST/EAST THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE
NORTH OVER THE WATERS INTO EARLY FRIDAY...WITH WIND SPEEDS
APPROACHING 15-20 KTS OVER NORTHERN SC WATERS AND SEAS BUILDING TO
3-4 FT. ENHANCED EAST/NORTHEAST FLOW MAY CONTINUE INTO SATURDAY
AS A COASTAL TROUGH DEVELOPS OFFSHORE AND GRADUALLY SHIFTS OVER LAND.
RIP CURRENTS...WE HAVE MAINTAINED A MODERATE RISK AT THE BEACHES
THROUGH THIS EVENING...DUE TO SOUTH AND SW WINDS AT 15 TO 20 MPH
AND A 2 FOOT SWELL EVERY 10 SECONDS. THE RISK FOR TOMORROW HOWEVER
IS LOW WITH MUCH LESS WIND.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...DPB
LONG TERM...
AVIATION...JAQ
MARINE...JAQ/DPB
000
FXUS62 KGSP 190007
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
807 PM EDT TUE JUN 18 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION ON WEDNESDAY...BUT
WITHOUT ENOUGH MOISTURE TO EXPECT MORE THAN ISOLATED SHOWERS. MOIST
EASTERLY FLOW WILL THEN KEEP SOME RAIN CHANCES THRU LATE WEEK MAINLY
OVER THE MOUNTAINS. HIGH PRESSURE WILL BUILD OVER THE AREA FOR THE
WEEKEND...MAINTAINING A WARM AND MOIST AIRMASS WITH A CHANCE OF
SHOWERS AND THUNDERSTORMS EACH AFTERNOON.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
730 PM UPDATE...PRECIP ACTIVITY NOW CONFINED TO THE PIEDMONT SHOULD
CONTINUE TO MOVE OUT OF THE CWFA WITH FRONT PUSHING INTO THAT AREA.
ACTIVITY GENERALLY WEAKENING WITH LOSS OF HEATING ANYWAY. RAP AS
WELL AS LOCAL WRF MODEL DO NOT SHOW ANY FURTHER DEVELOPMENT THIS
EVENING...AND WINDS ARE DRY AND DOWNSLOPING ANYWAY. STILL DO THINK
SOME OF THE REMAINING CU IN EAST TN AND THE MTNS OF WNC WILL REMAIN
AS PATCHY STRATUS FOR MUCH OF THE NIGHT...WITH CONVECTIVE DEBRIS
SPREADING ACROSS THE SE HALF OF THE CWFA TOO. KEPT PCLDY-MCLDY SKIES
OVERNIGHT AS A RESULT.
AS OF 230 PM EDT TUESDAY...A BIT OF A TRICKY FCST THIS AFTERNOON AND
EARLY EVENING. THE OVERALL PATTERN IS WELL AGREED UPON BY THE
MODELS...HOWEVER CONFIDENCE IN THE EVOLUTION OF S/W ENERGY ACROSS
THE CWFA IS NOT VERY HIGH DUE TO MODEL DIFFERENCES. THE LATEST RADAR
SHOWS AN UNSTABLE AIRMASS TO THE WEST BECOMING INCREASINGLY UNSTABLE
INTO THE WRN ZONES. VSBY SAY SHOW GOOD CLEARING AND HEATING TAKING
PLACE...BUT IN A DEEPLY MOIST ATMOS SBCAPE VALUES WILL LIKELY REACH
ONLY MOD LEVELS. THIS IS A LITTLE EVIDENT IN THE LOW TOP CONV SEEN
TO THE WEST. IN ANY REGARD...WILL ANTICIPATE TSTMS DEVELOPING AHEAD
OF THE WEAK COLD FRONT AND DEPENDING ON THE STRENGTH OF THE CROSS
S/W ENERGY...SOME OF THESE COULD BECOME STRONG TO SEVERE THIS
AFTERNOON. THE MAIN THREAT WOULD BE LARGE HAIL AND PERHAPS DAMAGING
WINDS AS DRIER AIR WORKS INTO THE MLVLS. EXPECT A WIND SHIFT ACROSS
THE MTNS AROUND 00Z AND INTO THE UPSTATE NEAR 05Z. THIS WILL
SUPPRESS ANY ACTIVITY TO THE SOUTH WITH A LOWER THETA/E AIRMASS
MIXING IN. SOME PATCHY DENSE FG IS POSSIBLE AROUND DAYBREAK IN THE
MTN VALLEYS AS THE PGRAD IS NOT REAL TIGHT BEHIND THE FRONT AND
BROADENS THROUGH 12Z.
A CP HIGH WILL WORK SOUTH INTO THE OH VALLEY TOMORROW AND PUSH A
BACKDOOR COLD FRONT INTO THE NRN ZONES BY THE AFTERNOON. THERE IS
NOT MUCH MOISTURE AVAILABLE WITH THIS SYSTEM SO WILL EXPECT THE BEST
PRECIP CHANCES ACROSS THE MTNS...WHERE AN E/LY UPSLOPE FLOW BRINGS
IN ATL MOISTURE. POPS HAVE BEEN HELD TO SLIGHT/CHANCE ACROSS THE
MTNS AND SLIGHT ELSEWHERE...WITH MAINLY -SHRA AND PERHAPS A MODERATE
THUNDERSTORM OR TWO ACROSS THE FHILLS AND MTNS. MAX TEMPS SHOULD
STILL BE A COUPLE DEGREES BELOW NORMAL WITH THE NE/LY SFC FLOW AND
AIRMASS MIXING.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 200 PM EDT TUESDAY...THE SHORT TERM WILL BE DOMINATED BY
SURFACE HIGH PRESSURE THAT WILL SET UP CAMP OFF THE NEW ENGLAND
COAST WHICH WILL REMAIN RIDGED SWD INTO THE SOUTHERN APPALACHIANS
THROUGH FRI. THE UPPER AIR PATTERN WILL BE ALMOST INDETERMINATE IN
THE DEEP SOUTH WITH VERY WEAK FLOW. THE AREA WILL BE BETWEEN A
TROUGH WELL TO THE NE AND AN UPPER RIDGE OVER THE SOUTHERN PLAINS.
HENCE...NO SIGNIFCANT UPPER FORCING IS ANTICIPATED. MODEL TIME
HEIGHTS INDICATE THAT MOISTURE WILL REMAIN RELATIVELY HIGH IN THE
BOUNDARY LAYER WITH DRYING ESSENTAILLY ABOVE 10KFT THROUGH THU NIGHT.
HOWEVER...MOISTURE IN THE COLUMN IS FORECAST TO DECREASE ON FRI.
HENCE...THE WEATHER SHOULD BE DRIVEN BY MAINLY BY THE LOW LEVEL WIND
FLOW AND ANY MECHANICAL LIFT IT MUSTERS...PLUS DIURNAL HEATING.
THEREFORE...MAINLY DIURNAL/SCATTERED CONVECTION IS EXPECTED PRIMARILY
OVER THE MOUNTAINS...WITH PERHAPS A DOWN TICK IN COVERAGE ON FRI
AFTERNOON DUE TO THE DRYER AIR. WITH THE WEAK UPSLOPE FLOW...SOME
NOCTURNAL WIDELY SCATTERED SHOWERS WILL REMAIN POSSIBLE OVER THE
MOUNTAINS WED/THU NIGHTS. USED AN ALLBLEND APPROACH TO TEMPERATURES
WHICH PRODUCED MAX TEMPS ON THU AND FRI ABOUT A CATEGORY BELOW
AVERAGE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 2 PM TUESDAY...THE MAIN FEATURE FOR THE EXTENDED PERIOD IS A
RIDGE OF HIGH PRESSURE THAT WILL SET UP OVER THE SOUTHEASTERN CONUS
OVER THE WEEKEND AND INTO MONDAY. THE BERMUDA HIGH WILL REMAIN
SITUATED OVER THE ATLANTIC OFF THE EAST COAST...SETTING UP A MOIST
SOUTHEASTERLY TO SOUTHWESTERLY LOW-LEVEL FLOW REGIME FOR THE REGION.
THIS WILL DRIVE MAINLY DIURNAL CONVECTION FOR THE PERIOD...WITH
GREATER CHANCE POPS FAVORING THE HIGHER ELEVATIONS EACH AFTERNOON
THROUGH THE MIDDLE OF NEXT WEEK. THE PERSISTENT RIDGE WILL ALLOW FOR
A SLIGHT WARMING TREND...WITH TEMPS NEAR TO SLIGHTLY ABOVE AVERAGE
BY THE END OF THE EXTENDED PERIOD.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...WINDS WILL SHIFT TO NW QUADRANT THIS EVENING AS FRONTAL
BOUNDARY ARRIVES...BUT TIMING TOUGH WITH TSTM ACTIVITY ACRS THE
REGION. HAVE SETTLED ON 03Z BASED MAINLY ON GFS MOS AND NAM. SOME
SHOWERS PRIOR TO THIS TIME AS WELL THOUGH VSBY SHUD REMAIN VFR.
DRIER AIR WILL WORK IN TONIGHT BUT SOME CLOUD COVER WILL LIKELY
REMAIN GIVEN AMT OF CONVECTIVE DEBRIS AT THIS TIME JUST BEFORE
SUNSET. DOWNSLOPING ON THE NW WINDS WILL LIMIT CLOUD DEVELOPMENT AND
GUIDANCE IN DECENT AGREEMENT THAT BKN CIG WILL REMAIN VFR. THIS WILL
MIX UP TO 050-060 WED MRNG. ISOLATED -SHRA AROUND THE AREA TMRW BUT
NOT WORTHY OF A TAF MENTION. LIGHT NLY WINDS FOLLOWING SHIFT.
ELSEWHERE...SHOWER/THUNDER CHANCES VERY SMALL AT TAF SITES THIS
EVENING AS DRIER...MORE STABLE AIR PUSHES IN BEHIND A COLD FRONT.
SITES THAT HAVE NOT ALREADY SEEN SHIFT TO NW WILL SEE IT BY EARLY
WED MRNG. LEFTOVER LOW CU OVER THE MTNS MAY CONGEAL INTO A MORE
SOLID DECK THIS EVENING BUT WITH THE DRY AND DOWNSLOPING FLOW CIGS
UNLIKELY TO LOWER MUCH...SO KEPT VFR CIGS AT ALL SITES. FAIRLY
STRONG SIGNAL FROM GUIDANCE THAT SOME FOG WILL FORM IN THE
MTNS/FOOTHILLS. WENT PREVAILING MVFR WITH TEMPO IFR AT KAVL/KHKY.
MIDLEVEL CIGS EXPECTED TOMORROW WITH ENUF CU DEVELOPMENT TO EXPECT
SOME ISOLATED SHOWERS...BUT WITH COVERAGE TOO LOW TO INCLUDE IN TAFS.
OUTLOOK...MOIST EASTERLY FLOW WILL SET UP WED NIGHT LEADING TO LOW
STRATUS ACROSS MUCH OF THE AREA THU MORNING WITH RESTRICTIONS LIKELY.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT HIGH 94% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 91% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 72% HIGH 81% HIGH 96% HIGH 100%
KHKY HIGH 94% HIGH 97% HIGH 97% HIGH 100%
KGMU HIGH 97% HIGH 88% HIGH 100% HIGH 100%
KAND HIGH 100% MED 74% HIGH 87% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...VISIN
AVIATION...WIMBERLEY
000
FXUS62 KCAE 182327
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
727 PM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SURFACE FRONT ACROSS THE UPSTATE SOUTH CAROLINA NORTHEAST INTO
WESTERN NORTH CAROLINA. CONVECTION AHEAD OF FRONT HAS BEEN
SCATTERED LATE THIS AFTERNOON/EVENING IN MODERATELY UNSTABLE AIR
MASS. CLUSTER IN NORTH GEORGIA INCREASING AT 22Z AND WILL MOVE
INTO THE CSRA...SO INCREASE POPS THERE OTHERWISE SCATTERED/CHANCE
POPS.
STORMS HAVE A HISTORY OF PRODUCING STRONG GUSTY WINDS. DOWNDRAFT
CAPE WAS HIGHER EARLIER...SO THREAT FOR WIND MAY BE DECREASING.
HEAVY RAIN THREAT CONTINUES WITH PRECIPITABLE WATER NEAR 2.00
INCHES.
WITH CLOUDS PERSISTING OVERNIGHT EXPECT LOW TEMPERATURES AROUND
70.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
UPPER TROUGH OVER THE REGION WEDNESDAY MOVES EAST BY THURSDAY AS
UPPER RIDGE STRENGTHENS OUT WEST BY THURSDAY NIGHT. SHORT WAVE DRAGS
A WEAK COLD FRONT THROUGH THE REGION WEDNESDAY. THE FRONT MOVES TO
THE SOUTH WEDNESDAY NIGHT AND ANOTHER QUITE WEAK SHORT WAVE DROPS
SOUTHWARD THURSDAY AND THURSDAY NIGHT. PLAN ON A 20-30 PERCENT CHANCE
OF SHOWERS AND THUNDERSTORMS WEDNESDAY AND A 20 PERCENT CHANCE
THURSDAY. EXPECT DIURNAL MAINLY LATE AFTERNOON AND EARLY EVENING
CONVECTIVE ACTIVITY. ALTHOUGH CAE AREA NOT OUTLOOKED FOR SEVERE
STORMS WEDNESDAY AFTERNOON...AFTERNOON SURFACE HEATING WITH TEMPERATURES
IN THE UPPER 80S TO NEAR 90 COULD CAUSE STEEPENING LAPSE RATES AND
CAUSE A FEW STRONG THUNDERSTORMS TO DEVELOP. ATMOSPHERE IS A
LITTLE DRIER WITH PWAT VALUES DOWN FROM 2.0 INCHES TODAY TO ABOUT
1.5 INCHES ON WEDNESDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT AS EAST COAST UPPER TROUGH
FRIDAY EXITS TO THE EAST AND UPPER RIDGE BUILDS ACROSS THE REGION
SATURDAY THROUGH TUESDAY. WITH UPPER RIDGE IN THE VICINITY...
TEMPERATURES SHOULD ON THE RISE. HIGHS UPPER 80S FRIDAY WILL
INCREASE TO THE LOWER 90S BY MONDAY AND TUESDAY. OVERNIGHT LOWS
ARE EXPECTED TO BE IN THE UPPER 60S TO AROUND 70. MAINLY DIURNAL
CONVECTIVE ACTIVITY DURING THE PERIOD AS EXPECT A SLIGHT CHANCE
OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. SO...FAIRLY
TYPICAL SUMMER-LIKE CONDITIONS AS THE SUMMER SOLSTICE APPROACHES.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR AT THE TERMINALS CURRENTLY. RADAR INDICATES A SEVERE
THUNDERSTORM COMPLEX NW OF DNL/AGS...MOVING EAST. ADDITIONAL SHOWERS
AND THUNDERSTORMS STRETCH FROM THERE SW ACROSS CENT GA. WILL HANDLE
WITH VCTS AND A TEMPO SHRA MENTION ANT DNL/AGS.
OTHERWISE...ONCE CONVECTION ASSOCIATED WITH A FRONTAL BOUNDARY
DISSIPATES LATER TONIGHT...FOCUS WILL SHIFT TO ANY FOG/STRATUS
THREAT FOR LATE TONIGHT/EARLY WED. LATEST GUIDANCE GENERALLY
POINTING TO POSSIBILITIES OF MVFR CONDITIONS.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR WEDNESDAY. SOME DRIER
AIR WILL ENTER OUR FORECAST AREA BEHIND A WEAK FRONT...WITH CHANCES
OF CONVECTION WEDNESDAY MAINLY TO OUR SOUTH. CHANCES TOO LOW TO
INCLUDE MENTION IN TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...SLIGHT CHANCE OF MAINLY
AFTERNOON/EVENING THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 182221
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
621 PM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SURFACE FRONT ACROSS THE UPSTATE SOUTH CAROLINA NORTHEAST INTO
WESTERN NORTH CAROLINA. CONVECTION AHEAD OF FRONT HAS BEEN
SCATTERED LATE THIS AFTERNOON/EVENING IN MODERATELY UNSTABLE AIR
MASS. CLUSTER IN NORTH GEORGIA INCREASING AT 22Z AND WILL MOVE
INTO THE CSRA...SO INCREASE POPS THERE OTHERWISE SCATTERED/CHANCE
POPS.
STORMS HAVE A HISTORY OF PRODUCING STRONG GUSTY WINDS. DOWNDRAFT
CAPE WAS HIGHER EARLIER...SO THREAT FOR WIND MAY BE DECREASING.
HEAVY RAIN THREAT CONTINUES WITH PRECIPITABLE WATER NEAR 2.00
INCHES.
WITH CLOUDS PERSISTING OVERNIGHT EXPECT LOW TEMPERATURES AROUND
70.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
UPPER TROUGH OVER THE REGION WEDNESDAY MOVES EAST BY THURSDAY AS
UPPER RIDGE STRENGTHENS OUT WEST BY THURSDAY NIGHT. SHORT WAVE DRAGS
A WEAK COLD FRONT THROUGH THE REGION WEDNESDAY. THE FRONT MOVES TO
THE SOUTH WEDNESDAY NIGHT AND ANOTHER QUITE WEAK SHORT WAVE DROPS
SOUTHWARD THURSDAY AND THURSDAY NIGHT. PLAN ON A 20-30 PERCENT CHANCE
OF SHOWERS AND THUNDERSTORMS WEDNESDAY AND A 20 PERCENT CHANCE
THURSDAY. EXPECT DIURNAL MAINLY LATE AFTERNOON AND EARLY EVENING
CONVECTIVE ACTIVITY. ALTHOUGH CAE AREA NOT OUTLOOKED FOR SEVERE
STORMS WEDNESDAY AFTERNOON...AFTERNOON SURFACE HEATING WITH TEMPERATURES
IN THE UPPER 80S TO NEAR 90 COULD CAUSE STEEPENING LAPSE RATES AND
CAUSE A FEW STRONG THUNDERSTORMS TO DEVELOP. ATMOSPHERE IS A
LITTLE DRIER WITH PWAT VALUES DOWN FROM 2.0 INCHES TODAY TO ABOUT
1.5 INCHES ON WEDNESDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT AS EAST COAST UPPER TROUGH
FRIDAY EXITS TO THE EAST AND UPPER RIDGE BUILDS ACROSS THE REGION
SATURDAY THROUGH TUESDAY. WITH UPPER RIDGE IN THE VICINITY...
TEMPERATURES SHOULD ON THE RISE. HIGHS UPPER 80S FRIDAY WILL
INCREASE TO THE LOWER 90S BY MONDAY AND TUESDAY. OVERNIGHT LOWS
ARE EXPECTED TO BE IN THE UPPER 60S TO AROUND 70. MAINLY DIURNAL
CONVECTIVE ACTIVITY DURING THE PERIOD AS EXPECT A SLIGHT CHANCE
OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. SO...FAIRLY
TYPICAL SUMMER-LIKE CONDITIONS AS THE SUMMER SOLSTICE APPROACHES.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
VFR AT THE TERMINALS CURRENTLY. RADAR INDICATES A THUNDERSTORM WILL
REMAIN NORTH OF CAE/CUB IN THE NEAR TERM. ADDITIONAL CONVECTIVE
ACTIVITY OVER EAST CENTRAL GA MOVING EAST TOWARDS THE CSRA. WILL
HAVE TO WATCH THIS FOR POSSIBLE INCLUSION IN AGS/DNL TAF EARLY THIS
EVENING. OTHERWISE...ONCE CONVECTION ASSOCIATED WITH A WEAK FRONTAL
PASSAGES DISSIPATES LATER TONIGHT BY AROUND MIDNIGHT...FOCUS WILL
SHIFT TO ANY FOG/STRATUS THREAT FOR LATE TONIGHT/EARLY WED. LATEST
GUIDANCE GENERALLY POINTING TO POSSIBILITIES OF MVFR TO IFR
CIGS...WITH POSSIBLE MVFR VSBYS. WILL EXAMINE HIGH RES SHORT TERM
MODELS LATER THIS EVENING. AFTER ANY MORNING RESTRICTIONS...EXPECT
VFR WEDNESDAY. SOME DRIER AIR WILL ENTER OUR FORECAST AREA BEHIND A
WEAK FRONT...WITH CHANCES OF CONVECTION WEDNESDAY MAINLY TO OUR
SOUTH. CHANCES TOO LOW TO INCLUDE MENTION IN TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...SLIGHT CHANCE OF MAINLY
AFTERNOON/EVENING THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 182042
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
442 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE EAST ACROSS THE AREA
THROUGH THIS EVENING...DRIVING SCATTERED SHOWERS AND THUNDERSTORMS.
ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE REGION ON
WEDNESDAY...BUT WITH SOME DRYING OF THE ATMOSPHERE. HIGH PRESSURE
WILL BUILD OVER THE AREA FOR THE WEEKEND...MAINTAINING A WARM AND
MOIST AIRMASS WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH
AFTERNOON.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
400 PM UPDATE...CATEGORICAL POPS SEEM APPROPRIATE FOR THE
MTNS/FOOTHILLS OVER THE NEXT HOUR OR SO...BUT LOWERED THEM A TAD TO
ACCOUNT FOR SOME GAPS IN COVERAGE. ACTIVITY WILL MOVE INTO THE
CLEARER AND MORE UNSTABLE PIEDMONT BEFORE INSTABILITY STARTS TO DROP
OFF WITH THE SETTING SUN...SO EXPANDED LOW CAT POPS INTO THE
PIEDMONT BRIEFLY AS POPS DIMINISH IN THE WEST. ADJUSTED TEMPS
SLIGHTLY GOING INTO EVENING BASED ON 4 PM OBS. TRIED TO ACCOUNT FOR
CLOUD COVER HOLDING TEMPS NEARLY STEADY IN SOME PLACES...AS WELL AS
OUTFLOW POTENTIALLY COOLING THINGS OFF IN THE WARMER AREAS IN THE
LOWER FOOTHILLS AND PIEDMONT.
AS OF 230 PM EDT TUESDAY...A BIT OF A TRICKY FCST THIS AFTERNOON AND
EARLY EVENING. THE OVERALL PATTERN IS WELL AGREED UPON BY THE
MODELS...HOWEVER CONFIDENCE IN THE EVOLUTION OF S/W ENERGY ACROSS
THE CWFA IS NOT VERY HIGH DUE TO MODEL DIFFERENCES. THE LATEST RADAR
SHOWS AN UNSTABLE AIRMASS TO THE WEST BECOMING INCREASINGLY UNSTABLE
INTO THE WRN ZONES. VSBY SAY SHOW GOOD CLEARING AND HEATING TAKING
PLACE...BUT IN A DEEPLY MOIST ATMOS SBCAPE VALUES WILL LIKELY REACH
ONLY MOD LEVELS. THIS IS A LITTLE EVIDENT IN THE LOW TOP CONV SEEN
TO THE WEST. IN ANY REGARD...WILL ANTICIPATE TSTMS DEVELOPING AHEAD
OF THE WEAK COLD FRONT AND DEPENDING ON THE STRENGTH OF THE CROSS
S/W ENERGY...SOME OF THESE COULD BECOME STRONG TO SEVERE THIS
AFTERNOON. THE MAIN THREAT WOULD BE LARGE HAIL AND PERHAPS DAMAGING
WINDS AS DRIER AIR WORKS INTO THE MLVLS. EXPECT A WIND SHIFT ACROSS
THE MTNS AROUND 00Z AND INTO THE UPSTATE NEAR 05Z. THIS WILL
SUPPRESS ANY ACTIVITY TO THE SOUTH WITH A LOWER THETA/E AIRMASS
MIXING IN. SOME PATCHY DENSE FG IS POSSIBLE AROUND DAYBREAK IN THE
MTN VALLEYS AS THE PGRAD IS NOT REAL TIGHT BEHIND THE FRONT AND
BROADENS THROUGH 12Z.
A CP HIGH WILL WORK SOUTH INTO THE OH VALLEY TOMORROW AND PUSH A
BACKDOOR COLD FRONT INTO THE NRN ZONES BY THE AFTERNOON. THERE IS
NOT MUCH MOISTURE AVAILABLE WITH THIS SYSTEM SO WILL EXPECT THE BEST
PRECIP CHANCES ACROSS THE MTNS...WHERE AN E/LY UPSLOPE FLOW BRINGS
IN ATL MOISTURE. POPS HAVE BEEN HELD TO SLIGHT/CHANCE ACROSS THE
MTNS AND SLIGHT ELSEWHERE...WITH MAINLY -SHRA AND PERHAPS A MODERATE
THUNDERSTORM OR TWO ACROSS THE FHILLS AND MTNS. MAX TEMPS SHOULD
STILL BE A COUPLE DEGREES BELOW NORMAL WITH THE NE/LY SFC FLOW AND
AIRMASS MIXING.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 200 PM EDT TUESDAY...THE SHORT TERM WILL BE DOMINATED BY
SURFACE HIGH PRESSURE THAT WILL SET UP CAMP OFF THE NEW ENGLAND
COAST WHICH WILL REMAIN RIDGED SWD INTO THE SOUTHERN APPALACHIANS
THROUGH FRI. THE UPPER AIR PATTERN WILL BE ALMOST INDETERMINATE IN
THE DEEP SOUTH WITH VERY WEAK FLOW. THE AREA WILL BE BETWEEN A
TROUGH WELL TO THE NE AND AN UPPER RIDGE OVER THE SOUTHERN PLAINS.
HENCE...NO SIGNIFCANT UPPER FORCING IS ANTICIPATED. MODEL TIME
HEIGHTS INDICATE THAT MOISTURE WILL REMAIN RELATIVELY HIGH IN THE
BOUNDARY LAYER WITH DRYING ESSENTAILLY ABOVE 10KFT THROUGH THU NIGHT.
HOWEVER...MOISTURE IN THE COLUMN IS FORECAST TO DECREASE ON FRI.
HENCE...THE WEATHER SHOULD BE DRIVEN BY MAINLY BY THE LOW LEVEL WIND
FLOW AND ANY MECHANICAL LIFT IT MUSTERS...PLUS DIURNAL HEATING.
THEREFORE...MAINLY DIURNAL/SCATTERED CONVECTION IS EXPECTED PRIMARILY
OVER THE MOUNTAINS...WITH PERHAPS A DOWN TICK IN COVERAGE ON FRI
AFTERNOON DUE TO THE DRYER AIR. WITH THE WEAK UPSLOPE FLOW...SOME
NOCTURNAL WIDELY SCATTERED SHOWERS WILL REMAIN POSSIBLE OVER THE
MOUNTAINS WED/THU NIGHTS. USED AN ALLBLEND APPROACH TO TEMPERATURES
WHICH PRODUCED MAX TEMPS ON THU AND FRI ABOUT A CATEGORY BELOW
AVERAGE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 2 PM TUESDAY...THE MAIN FEATURE FOR THE EXTENDED PERIOD IS A
RIDGE OF HIGH PRESSURE THAT WILL SET UP OVER THE SOUTHEASTERN CONUS
OVER THE WEEKEND AND INTO MONDAY. THE BERMUDA HIGH WILL REMAIN
SITUATED OVER THE ATLANTIC OFF THE EAST COAST...SETTING UP A MOIST
SOUTHEASTERLY TO SOUTHWESTERLY LOW-LEVEL FLOW REGIME FOR THE REGION.
THIS WILL DRIVE MAINLY DIURNAL CONVECTION FOR THE PERIOD...WITH
GREATER CHANCE POPS FAVORING THE HIGHER ELEVATIONS EACH AFTERNOON
THROUGH THE MIDDLE OF NEXT WEEK. THE PERSISTENT RIDGE WILL ALLOW FOR
A SLIGHT WARMING TREND...WITH TEMPS NEAR TO SLIGHTLY ABOVE AVERAGE
BY THE END OF THE EXTENDED PERIOD.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
AT KCLT...THE UPPER S/W ENERGY IS BEGINNING TO INTERACT WITH
INCREASING INSTABILITY TO THE WEST OF THE TERMINAL AND THIS SHOULD
PRODUCE SOME DEEPER CELLS AND TSTMS ACROSS THE AREA THRU SUNSET.
GIVEN ABUNDANT MOISTURE ENABLING ESPECIALLY HIGH RAINFALL
RATES...BRIEF IFR VSBY IS LIKELY TO OCCUR DURING TS IF THEY PASS
OVER THE FIELD. MOST ACTIVITY TO THE N OF THE FIELD ATTM SO GUSTS OF
OUTFLOW FROM THE N POSSIBLE TOO. EXPECT MAINLY -SHRA IN THE VICINITY
AFT 01Z. WITH THE PRECIP TODAY AND POSSIBLY THIS EVENING...WILL
INCLUDE MVFR FG FOR A FEW HRS NEAR DAYBREAK EVEN WITH A MIX OF A
LOWER T/TD AIRMASS.
ELSEWHERE...STARTING TO SEE THE CONV ACTIVITY TO THE WEST INCREASE
IN COVERAGE AND INTENSITY..WHILE A ULVL WAVE WILL PUSH ALL THIS
EAST THROUGH THE OVERNIGHT. EXPECT PERIODIC THUNDER AT ALL SITES
BEGINNING AFT 18Z OR SO AND CONTINUING THROUGH THE EARLY
EVENING...PRODUCING ISOLATED IFR VSBYS IN HVY RA. WILL COVER
REMAINING LOW END ACTIVITY BEFORE THE COLD FRONT CROSSES WITH
VCSH/S. ALL SITES SHOULD SEE RESTRICTIVE VSBY OR CIGS IN THE MVFR
RANGE AROUND DAYBREAK...WITH KAVL LIKELY EXPERIENCING IFR CONDS.
OUTLOOK...A MODERATELY UNSTABLE ATMOSPHERE COMBINED WITH EASTERLY
FLOW MAY LEAD TO SHOWER AND THUNDERSTORM DEVELOPMENT
MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 100% LOW 53% HIGH 100%
KGSP HIGH 100% HIGH 95% MED 68% HIGH 85%
KAVL HIGH 93% HIGH 96% HIGH 80% HIGH 85%
KHKY HIGH 100% HIGH 100% MED 67% HIGH 85%
KGMU HIGH 100% HIGH 88% LOW 45% HIGH 85%
KAND HIGH 100% HIGH 98% MED 66% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...VISIN
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...VISIN
AVIATION...SBK/WIMBERLEY
000
FXUS62 KCHS 182031
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
431 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT...THEN
SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH
PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND
SETTLE OVER THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
TONIGHT...THE LARGE SCALE PATTERN FEATURES AN EXPANSIVE TROUGH
OVER THE EASTERN STATES...WITH A DECENT MID LEVEL IMPULSE TO MOVE
THROUGH THIS EVENING. THIS SHORT WAVE IN SYNC WITH A COUPLED JET
STRUCTURE OVER EASTERN TN AND WESTERN NC IS PROVIDING AMPLE
FORCING FOR ASCENT...AND WILL DO SHOW INTO THIS EVENING. AT THE
SURFACE THERE IS GOOD FORCING AS WELL...THE RESULT OF AN
INCREASING 20-30 KT LOW LEVEL JET IN ADVANCE OF A SLUGGISH MOVING
COLD FRONT EXTENDING SW FROM A WAVE OF LOW PRESSURE IN WEST-
CENTRAL NC. VARIOUS SMALL SCALE BOUNDARIES ARE EVIDENT...THE
RESULTANT SEA BREEZE WHICH IS CRANKING UP NEAR 20
MPH...DIFFERENTIAL HEATING BOUNDARIES...LAKE MARION/MOULTRIE
BREEZES AND OUTFLOWS FROM BOTH ONGOING AND UPSTREAM CONVECTION.
THIS ALL LEADS TO SCATTERED TO LIKELY POPS OVER MUCH OF THE
FORECAST AREA INTO THIS EVENING WHEN THE SHORT WAVE PULLS EAST AND
COVERAGE DIMINISHES.
A FEW OF THE STORMS WILL BE STRONG OR SEVERE...WITH DECENT
THERMODYNAMICS...SUCH AS SBCAPES OF 2000-2500 J/KG...LIFTED
INDICES -6 TO -8C AND BETTER MID LEVEL LAPSE RATES THAN LATE AT
6-6.5 C/KM. THE UPDRAFTS WILL BECOME ENHANCED BY THE DYNAMICS
ALOFT AND THE UPWARD MOTION CAUSED BY THE LIFTING DUE TO THE
BOUNDARIES IN THE LOWER TROPOSPHERE. THIS APPEARS MOST LIKELY NEAR
KCHS WHERE STORMS...OUTFLOWS AND THE SE BREEZE COLLIDE. WITH SOME
DRY AIR AS SHOWN ON SOUNDINGS BETWEEN ABOUT 8-18K FEET...THE
RESULTING DCAPES ARE AS HIGH AS 800-1200 J/KG. THUS MICROBURSTS
ARE THE MAIN WEATHER HAZARD THROUGH ABOUT 8 OR 9 PM...WITH
ISOLATED SEVERE WEATHER TO PERSIST DURING THIS TIME.
TEMPORARY NVA DEVELOPS IN WAKE OF THE SHORT WAVE LATER THIS
EVENING AND OVERNIGHT...BUT THE COLD FRONT DRAWS CLOSER TO THE
CWFA LATE. WITH THE FORECAST AREA IN CLOSE PROXIMITY TO THE RIGHT
REAR QUAD OF THE UPPER 60-75 KT NEAR THE APPALACHIANS...WE/LL HAVE
TO HOLD ONTO AT LEAST SMALL POPS DURING THE LATE EVENING AND
OVERNIGHT HOURS. THE FRONT THOUGH BECOMES ALIGNED WITH THE FLOW
ALOFT AS IT POSITIONS ITSELF MORE EAST-WEST ORIENTED...TRAILING
FROM THE SURFACE WAVE THAT CLOSES INTO A WEAK LOW OFF THE MID
ATLANTIC REGION OVERNIGHT. GIVEN THAT THERE LOOKS TO BE DECENT
CINH IN PLACE AND SOME STABILIZATION OCCURS THIS LOOKS TO LIMIT
THE STRENGTH OF ANY NOCTURNAL ACTIVITY.
MEANWHILE...PWATS ARE NEAR THE 75TH PERCENTILE THROUGH
TONIGHT...AS HIGH AS 1.9 TO 2.0 INCHES. WHILE THERE IS ENOUGH
PROGRESSION TO SHOWERS AND T-STORMS...THE SATURATED CONDITIONS
COULD NONETHELESS STILL PRODUCE SOME LOCALLY HEAVY RAINFALL. AND
SOME OF THE GROUNDS ARE STILL RATHER SOAKED...MOST NOTABLY A
SWATH OF 1-3 INCH AND LOCALLY HIGHER AMOUNTS ACROSS MUCH OF THE
NORTHERN AND CENTRAL ZONES FROM RAINS WITHIN THE PAST 24-36 HOURS.
SO IT MIGHT NOT TAKE MUCH TO PRODUCE AT LEAST MINOR FLOODING
CONCERNS.
EVAPORATIVE COOLING DUE TO THE RAIN HAS BEEN IMPLIED IN THE HOURLY
TEMP GRIDS THROUGH THIS EVENING...WITH MID AND UPPER 70S WHERE
RAIN OCCURS THROUGH SUNSET. WHERE RAIN DOESN/T FALL TEMPS WILL
BE IN THE 80S FOR SEVERAL MORE HOURS. THEREAFTER...THE TEMP CURVE
WILL SHOW FAIRLY STEADY TEMPS...BEFORE LATE NIGHT HEAT LOSS IS
MAXIMIZED AND LOWS DROP TO THE LOWER AND MIDDLE 70S MOST
COMMUNITIES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY AND THURSDAY...A COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA BY WEDNESDAY MORNING
BEFORE GRADUALLY STALLING SOUTH OF THE REGION BY THURSDAY. AS THIS
OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL FORCING FROM AN H5
SHORTWAVE SHOULD FAVOR PERIODS OF SHOWERS/THUNDERSTORMS THROUGH MUCH
OF WEDNESDAY...ESPECIALLY ALONG/NEAR THE PASSING COLD FRONT. HAVE
THEREFORE INCREASED POPS TO 50-60 WEDNESDAY AFTERNOON MAINLY ALONG
COASTAL LOCATIONS IN SOUTHEAST GEORGIA CLOSER TO THE FRONT. AT THIS
TIME...CLOUD COVER WILL REMAIN A LIMITING FACTOR FOR STRONGER
THUNDERSTORMS TO DEVELOP OVER THE REGION. HOWEVER...WEAK WIND FIELDS
WILL LIKELY RESULT IN SLOW STORM MOTIONS THAT MAY CONTRIBUTE TO
HEAVY RAINFALL DURING A FEW THUNDERSTORMS.
A GRADUAL DECREASE IN OVERALL POPS SHOULD THEN OCCUR FROM NORTH TO
SOUTH WEDNESDAY NIGHT INTO THURSDAY AS THE FRONT SLOWLY SLIPS TO THE
SOUTH OF THE FORECAST AREA...BUT HAVE MAINTAINED A MENTION OF PRECIP
OVER ALL LOCATIONS THROUGH THURSDAY NIGHT...WITH 20 POPS OVER INLAND
SOUTH CAROLINA TO 30-40 POPS OVER LOCATIONS SOUTH OF INTERSTATE 16
IN GEORGIA. OVERALL HIGH TEMPS ARE EXPECTED TO PEAK IN THE MID/UPPER
80S OVER MOST LOCATIONS WEDNESDAY AND THURSDAY...WITH SLIGHTLY COOLER
TEMPS IN THE MID 80S OVER SOUTH CAROLINA BEHIND THE FRONT. OVERNIGHT
LOWS ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FRIDAY...SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
NORTH...WITH THE PATTERN EVENTUALLY TRANSITIONING INTO AN INLAND
WEDGE/COASTAL TROUGH TYPE SCENARIO. A FEW MODELS INDICATE A WEAK
WAVE/SFC LOW DEVELOPING ALONG THE STALLED FRONT JUST OFFSHORE LATE
MORNING/EARLY AFTERNOON BEFORE DRIFTING ONSHORE DURING THE EVENING.
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND/OR THUNDERSTORMS WILL
THEREFORE BE MAINTAINED IN THE CURRENT FORECAST...WITH HIGHEST
CHANCES OVER SOUTHEAST GEORGIA COUNTIES. OVERALL HIGH TEMPS SHOULD
REMAIN IN THE MID/UPPER 80S WITH SLIGHTLY COOLER TEMPS ALONG COASTAL
COUNTIES AND THE TRI COUNTY AREA DUE TO ENHANCED CLOUD COVER AND
HIGH PRESSURE NUDGING IN FROM THE NORTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
KCHS...A COLLISION OF BOUNDARIES WILL LIKELY TRIGGER STRONG TSRA AT
OR NEAR THE TERMINAL THIS EVENING...PRODUCING TEMPORARY FLIGHT
RESTRICTIONS DOWN INTO THE MVFR OR LOWER RANGE FROM 21Z TO 01Z. GUSTY
WINDS...HEAVY RAINS AND FREQUENT LIGHTNING WILL OCCUR. CONDITIONS
QUIET DOWN IN WAKE OF A SHORT WAVE FOR THE LATE EVENING AND
OVERNIGHT...BUT THE PROXIMITY TO A COLD FRONT WILL TRIGGER THE
RISK OF TSRA AND POSSIBLE FLIGHT RESTRICTIONS AGAIN LATE IN THE 18Z
TAF CYCLE.
KSAV...WE HAVE BACKED OFF A BIT ON THE RISK FOR TSRA AT THE
AIRFIELD INTO THIS EVENING. HOWEVER...CONVECTION IS STILL POSSIBLE
AND AMENDMENT MIGHT BE REQUIRED FOR A PERIOD OF SUB-VFR CONDITIONS
A COUPLE OF HOURS EITHER SIDE OF SUNSET THIS EVENING. AN
APPROACHING COLD FRONT WILL LIE NEARBY LATE WEDNESDAY MORNING AND
INTO THE AFTERNOON...AND ISOLATED TO SCATTERED CONVECTION LOOKS TO
FORM AGAIN.
EXTENDED AVIATION...MVFR CIGS/VSBYS POSSIBLE WEDNESDAY THROUGH
THURSDAY DUE TO SHOWERS AND/OR THUNDERSTORMS....WITH THE GREATEST
CHANCE BEING WEDNESDAY AFTERNOON. LOW CHANCE OF MVFR CIGS/VSBYS
FRIDAY AFTERNOON/EVENING WITH A COASTAL TROUGH/SFC LOW SHIFTING
ONSHORE.
&&
.MARINE...
TONIGHT...THE PRESSURE GRADIENT IS CONTINUING TO TIGHTEN BETWEEN
THE STRONG SUB-TROPICAL ATLANTIC RIDGE TO THE SE AND AN UPSTREAM
COLD FRONT TO THE NW. THAT ALONG WITH SEA BREEZE CIRCULATION IS
GENERATING SOME GUSTS NEAR AND OVER 20 KT AT VARIOUS COASTAL SITES
AND IN CHARLESTON HARBOR. THE PACKING OF THE ISOBARS WILL BECOME
GREATEST EARLY TONIGHT BETWEEN THE COLD FRONT AND ATLANTIC
HIGH...AS GEOSTROPHIC WINDS CLIMB TO 25-30 KT. THIS IS SUPPORTIVE
OF A MARGINAL SCA ACROSS OUR OUTER GA WATERS FOR SOME 6 FOOTERS
AND FREQUENT GUSTS OF 25 KT. THE OTHER WATERS LOOK TO REMAIN JUST
BELOW ANY HEADLINE CONDITIONS...WITH WINDS PEAKING AT 15 OR 20 KT
AND SEAS AT 3-5 FT.
WEDNESDAY THROUGH SATURDAY...WINDS/SEAS ARE EXPECTED TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA AS A COLD FRONT SHIFTS OVER THE
COASTAL WATERS WEDNESDAY BEFORE STALLING NEAR/OVER SOUTHERN GA
WATERS ON THURSDAY. AS THE FRONT SLOWLY SHIFTS SOUTH...SOUTHERLY
WINDS WILL VEER BEHIND THE FRONT AND EVENTUALLY BECOME
NORTHEAST/EAST THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE
NORTH OVER THE WATERS INTO EARLY FRIDAY...WITH WIND SPEEDS
APPROACHING 15-20 KTS OVER NORTHERN SC WATERS AND SEAS BUILDING TO
3-4 FT. ENHANCED EAST/NORTHEAST FLOW MAY CONTINUE INTO SATURDAY
AS A COASTAL TROUGH DEVELOPS OFFSHORE AND GRADUALLY SHIFTS OVER LAND.
RIP CURRENTS...WE HAVE MAINTAINED A MODERATE RISK AT THE BEACHES
THROUGH THIS EVENING...DUE TO SOUTH AND SW WINDS AT 15 TO 20 MPH
AND A 2 FOOT SWELL EVERY 10 SECONDS. THE RISK FOR TOMORROW HOWEVER
IS LOW WITH MUCH LESS WIND.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...DPB
LONG TERM...
AVIATION...
MARINE...
000
FXUS62 KCHS 181941
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
341 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT...THEN
SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH
PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND
SETTLE OVER THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
TONIGHT...THE LARGE SCALE PATTERN FEATURES AN EXPANSIVE TROUGH
OVER THE EASTERN STATES...WITH A DECENT MID LEVEL IMPULSE TO MOVE
THROUGH THIS EVENING. THIS SHORT WAVE IN SYNC WITH A COUPLED JET
STRUCTURE OVER EASTERN TN AND WESTERN NC IS PROVIDING AMPLE
FORCING FOR ASCENT...AND WILL DO SHOW INTO THIS EVENING. AT THE
SURFACE THERE IS GOOD FORCING AS WELL...THE RESULT OF AN
INCREASING 20-30 KT LOW LEVEL JET IN ADVANCE OF A SLUGGISH MOVING
COLD FRONT EXTENDING SW FROM A WAVE OF LOW PRESSURE IN WEST-
CENTRAL NC. VARIOUS SMALL SCALE BOUNDARIES ARE EVIDENT...THE
RESULTANT SEA BREEZE WHICH IS CRANKING UP NEAR 20
MPH...DIFFERENTIAL HEATING BOUNDARIES...LAKE MARION/MOULTRIE
BREEZES AND OUTFLOWS FROM BOTH ONGOING AND UPSTREAM CONVECTION.
THIS ALL LEADS TO SCATTERED TO LIKELY POPS OVER MUCH OF THE
FORECAST AREA INTO THIS EVENING WHEN THE SHORT WAVE PULLS EAST. A
FEW OF THE STORMS WILL BE STRONG OR SEVERE...WITH DECENT
THERMODYNAMICS...SUCH AS SBCAPES OF 2000-2500 J/KG...LIFTED
INDICES -6 TO -8C AND BETTER MID LEVEL LAPSE RATES THAN LATE AT
6-6.5 C/KM. THE UPDRAFTS WILL BECOME ENHANCED BY THE DYNAMICS
ALOFT AND THE UPWARD MOTION CAUSED BY THE LIFTING DUE TO THE
BOUNDARIES IN THE LOWER TROPOSPHERE. THIS TAPS INTO SOME DRY AIR
SHOWN ON SOUNDINGS BETWEEN ABOUT 8-18K FEET...WITH THE RESULTING
DCAPES AS HIGH AS 800-1200 J/KG. THUS MICROBURSTS ARE THE MAIN
WEATHER HAZARD THROUGH ABOUT 8 OR 9 PM...WITH ISOLATED SEVERE
WEATHER TO PERSIST DURING THIS TIME.
TEMPORARY NVA DEVELOPS IN WAKE OF THE SHORT WAVE LATER THIS
EVENING AND OVERNIGHT...BUT THE COLD FRONT DRAWS CLOSER TO THE
CWFA LATE. WITH THE FORECAST AREA IN CLOSE PROXIMITY TO THE RIGHT
REAR QUAD OF THE UPPER 60-75 KT NEAR THE APPALACHIANS...WE/LL HAVE
TO HOLD ONTO AT LEAST SMALL POPS DURING THE LATE EVENING AND
OVERNIGHT HOURS. THE FRONT THOUGH BECOMES ALIGNED WITH THE FLOW
ALOFT AS IT POSITIONS ITSELF MORE EAST-WEST ORIENTED...TRAILING
FROM THE SURFACE WAVE THAT CLOSES INTO A WEAK LOW OFF THE MID
ATLANTIC REGION OVERNIGHT. GIVEN THAT THERE LOOKS TO BE DECENT
CINH IN PLACE AND SOME STABILIZATION OCCURS THIS LOOKS TO LIMIT
THE STRENGTH OF ANY NOCTURNAL ACTIVITY.
MEANWHILE...PWATS ARE NEAR THE 75TH PERCENTILE THROUGH
TONIGHT...AS HIGH AS 1.9 TO 2.0 INCHES. WHILE THERE IS ENOUGH
PROGRESSION TO SHOWERS AND T-STORMS...THE SATURATED CONDITIONS
COULD NONETHELESS STILL PRODUCE SOME LOCALLY HEAVY RAINFALL. AND
SOME OF THE GROUNDS ARE STILL RATHER SOAKED...MOST NOTABLY A
SWATH OF 1-3 INCH AND LOCALLY HIGHER AMOUNTS ACROSS MUCH OF THE
NORTHERN AND CENTRAL ZONES FROM RAINS WITHIN THE PAST 24-36 HOURS.
SO IT MIGHT NOT TAKE MUCH TO PRODUCE AT LEAST MINOR FLOODING
CONCERNS.
EVAPORATIVE COOLING DUE TO THE RAIN HAS BEEN IMPLIED IN THE HOURLY
TEMP GRIDS THROUGH THIS EVENING...WITH MID AND UPPER 70S WHERE
RAIN OCCURS THROUGH SUNSET. WHERE RAIN DOESN/T FALL TEMPS WILL
BE IN THE 80S FOR SEVERAL MORE HOURS. THEREAFTER...THE TEMP CURVE
WILL SHOW FAIRLY STEADY TEMPS...BEFORE LATE NIGHT HEAT LOSS IS
MAXIMIZED AND LOWS DROP TO THE LOWER AND MIDDLE 70S MOST
COMMUNITIES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY AND THURSDAY...A COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA BY WEDNESDAY MORNING
BEFORE GRADUALLY STALLING SOUTH OF THE REGION BY THURSDAY. AS THIS
OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL FORCING FROM AN H5
SHORTWAVE SHOULD FAVOR PERIODS OF SHOWERS/THUNDERSTORMS THROUGH MUCH
OF WEDNESDAY...ESPECIALLY ALONG/NEAR THE PASSING COLD FRONT. HAVE
THEREFORE INCREASED POPS TO 50-60 WEDNESDAY AFTERNOON MAINLY ALONG
COASTAL LOCATIONS IN SOUTHEAST GEORGIA CLOSER TO THE FRONT. AT THIS
TIME...CLOUD COVER WILL REMAIN A LIMITING FACTOR FOR STRONGER
THUNDERSTORMS TO DEVELOP OVER THE REGION. HOWEVER...WEAK WIND FIELDS
WILL LIKELY RESULT IN SLOW STORM MOTIONS THAT MAY CONTRIBUTE TO
HEAVY RAINFALL DURING A FEW THUNDERSTORMS.
A GRADUAL DECREASE IN OVERALL POPS SHOULD THEN OCCUR FROM NORTH TO
SOUTH WEDNESDAY NIGHT INTO THURSDAY AS THE FRONT SLOWLY SLIPS TO THE
SOUTH OF THE FORECAST AREA...BUT HAVE MAINTAINED A MENTION OF PRECIP
OVER ALL LOCATIONS THROUGH THURSDAY NIGHT...WITH 20 POPS OVER INLAND
SOUTH CAROLINA TO 30-40 POPS OVER LOCATIONS SOUTH OF INTERSTATE 16
IN GEORGIA. OVERALL HIGH TEMPS ARE EXPECTED TO PEAK IN THE MID/UPPER
80S OVER MOST LOCATIONS WEDNESDAY AND THURSDAY...WITH SLIGHTLY COOLER
TEMPS IN THE MID 80S OVER SOUTH CAROLINA BEHIND THE FRONT. OVERNIGHT
LOWS ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FRIDAY...SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
NORTH...WITH THE PATTERN EVENTUALLY TRANSITIONING INTO AN INLAND
WEDGE/COASTAL TROUGH TYPE SCENARIO. A FEW MODELS INDICATE A WEAK
WAVE/SFC LOW DEVELOPING ALONG THE STALLED FRONT JUST OFFSHORE LATE
MORNING/EARLY AFTERNOON BEFORE DRIFTING ONSHORE DURING THE EVENING.
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND/OR THUNDERSTORMS WILL
THEREFORE BE MAINTAINED IN THE CURRENT FORECAST...WITH HIGHEST
CHANCES OVER SOUTHEAST GEORGIA COUNTIES. OVERALL HIGH TEMPS SHOULD
REMAIN IN THE MID/UPPER 80S WITH SLIGHTLY COOLER TEMPS ALONG COASTAL
COUNTIES AND THE TRI COUNTY AREA DUE TO ENHANCED CLOUD COVER AND
HIGH PRESSURE NUDGING IN FROM THE NORTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
CONVECTION WILL CONTINUE TO FIRE IN ADVANCE OF A COLD FRONT AND
ALONG NUMEROUS MESO-SCALE BOUNDARIES...WITH ADDITIONAL FORCING FOR
ASCENT TO RESULT FROM A SHORT WAVE THAT MOVES THROUGH LATE THIS
AFTERNOON/EVENING. WE HAVE SHOWN TEMPORARY FLIGHT RESTRICTIONS
FROM TSRA INTO THE MVFR RANGE FROM ABOUT 20-21Z THROUGH 24-01Z AT
BOTH SITES AS THE SHORT WAVE MOVES THROUGH. GUSTY WINDS...HEAVY
RAINS AND POSSIBLE IFR CONDITIONS WILL ALSO OCCUR. IN WAKE OF THE
SHORT WAVE THE AIRFIELDS WILL REMAIN VFR TONIGHT...BUT THE COLD
FRONT WILL APPROACH LATE TONIGHT/WEDNESDAY MORNING AND STALL. WITH
THE FRONT CLOSE BY ADDITIONAL SHRA/TSRA WILL DEVELOP AGAIN EARLY
WEDNESDAY. FLIGHT RESTRICTIONS ARE AGAIN POSSIBLE.
EXTENDED AVIATION...MVFR CIGS/VSBYS POSSIBLE WEDNESDAY THROUGH
THURSDAY DUE TO SHOWERS AND/OR THUNDERSTORMS....WITH THE GREATEST
CHANCE BEING WEDNESDAY AFTERNOON. LOW CHANCE OF MVFR CIGS/VSBYS
FRIDAY AFTERNOON/EVENING WITH A COASTAL TROUGH/SFC LOW SHIFTING
ONSHORE.
&&
.MARINE...
TONIGHT...THE PRESSURE GRADIENT IS CONTINUING TO TIGHTEN BETWEEN
THE STRONG SUB-TROPICAL ATLANTIC RIDGE TO THE SE AND AN UPSTREAM
COLD FRONT TO THE NW. THAT ALONG WITH SEA BREEZE CIRCULATION IS
GENERATING SOME GUSTS NEAR AND OVER 20 KT AT VARIOUS COASTAL SITES
AND IN CHARLESTON HARBOR. THE PACKING OF THE ISOBARS WILL BECOME
GREATEST EARLY TONIGHT BETWEEN THE COLD FRONT AND ATLANTIC
HIGH...AS GEOSTROPHIC WINDS CLIMB TO 25-30 KT. THIS IS SUPPORTIVE
OF A MARGINAL SCA ACROSS OUR OUTER GA WATERS FOR SOME 6 FOOTERS
AND FREQUENT GUSTS OF 25 KT. THE OTHER WATERS LOOK TO REMAIN JUST
BELOW ANY HEADLINE CONDITIONS...WITH WINDS PEAKING AT 15 OR 20 KT
AND SEAS AT 3-5 FT.
WEDNESDAY THROUGH SATURDAY...WINDS/SEAS ARE EXPECTED TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA AS A COLD FRONT SHIFTS OVER THE
COASTAL WATERS WEDNESDAY BEFORE STALLING NEAR/OVER SOUTHERN GA
WATERS ON THURSDAY. AS THE FRONT SLOWLY SHIFTS SOUTH...SOUTHERLY
WINDS WILL VEER BEHIND THE FRONT AND EVENTUALLY BECOME
NORTHEAST/EAST THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE
NORTH OVER THE WATERS INTO EARLY FRIDAY...WITH WIND SPEEDS
APPROACHING 15-20 KTS OVER NORTHERN SC WATERS AND SEAS BUILDING TO
3-4 FT. ENHANCED EAST/NORTHEAST FLOW MAY CONTINUE INTO SATURDAY
AS A COASTAL TROUGH DEVELOPS OFFSHORE AND GRADUALLY SHIFTS OVER LAND.
RIP CURRENTS...WE HAVE MAINTAINED A MODERATE RISK AT THE BEACHES
THROUGH THIS EVENING...DUE TO SOUTH AND SW WINDS AT 15 TO 20 MPH
AND A 2 FOOT SWELL EVERY 10 SECONDS. THE RISK FOR TOMORROW HOWEVER
IS LOW WITH MUCH LESS WIND.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...DPB
LONG TERM...WMS
AVIATION...
MARINE...
000
FXUS62 KGSP 181824
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
224 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE EAST ACROSS THE AREA
THROUGH THIS EVENING...DRIVING SCATTERED SHOWERS AND THUNDERSTORMS.
ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE REGION ON
WEDNESDAY...BUT WITH SOME DRYING OF THE ATMOSPHERE. HIGH PRESSURE
WILL BUILD OVER THE AREA FOR THE WEEKEND...MAINTAINING A WARM AND
MOIST AIRMASS WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH
AFTERNOON.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 230 PM EDT TUESDAY...A BIT OF A TRICKY FCST THIS AFTERNOON AND
EARLY EVENING. THE OVERALL PATTERN IS WELL AGREED UPON BY THE
MODELS...HOWEVER CONFIDENCE IN THE EVOLUTION OF S/W ENERGY ACROSS
THE CWFA IS NOT VERY HIGH DUE TO MODEL DIFFERENCES. THE LATEST RADAR
SHOWS AN UNSTABLE AIRMASS TO THE WEST BECOMING INCREASINGLY UNSTABLE
INTO THE WRN ZONES. VSBY SAY SHOW GOOD CLEARING AND HEATING TAKING
PLACE...BUT IN A DEEPLY MOIST ATMOS SBCAPE VALUES WILL LIKELY REACH
ONLY MOD LEVELS. THIS IS A LITTLE EVIDENT IN THE LOW TOP CONV SEEN
TO THE WEST. IN ANY REGARD...WILL ANTICIPATE TSTMS DEVELOPING AHEAD
OF THE WEAK COLD FRONT AND DEPENDING ON THE STRENGTH OF THE CROSS
S/W ENERGY...SOME OF THESE COULD BECOME STRONG TO SEVERE THIS
AFTERNOON. THE MAIN THREAT WOULD BE LARGE HAIL AND PERHAPS DAMAGING
WINDS AS DRIER AIR WORKS INTO THE MLVLS. EXPECT A WIND SHIFT ACROSS
THE MTNS AROUND 00Z AND INTO THE UPSTATE NEAR 05Z. THIS WILL
SUPPRESS ANY ACTIVITY TO THE SOUTH WITH A LOWER THETA/E AIRMASS
MIXING IN. SOME PATCHY DENSE FG IS POSSIBLE AROUND DAYBREAK IN THE
MTN VALLEYS AS THE PGRAD IS NOT REAL TIGHT BEHIND THE FRONT AND
BROADENS THROUGH 12Z.
A CP HIGH WILL WORK SOUTH INTO THE OH VALLEY TOMORROW AND PUSH A
BACKDOOR COLD FRONT INTO THE NRN ZONES BY THE AFTERNOON. THERE IS
NOT MUCH MOISTURE AVAILABLE WITH THIS SYSTEM SO WILL EXPECT THE BEST
PRECIP CHANCES ACROSS THE MTNS...WHERE AN E/LY UPSLOPE FLOW BRINGS
IN ATL MOISTURE. POPS HAVE BEEN HELD TO SLIGHT/CHANCE ACROSS THE
MTNS AND SLIGHT ELSEWHERE...WITH MAINLY -SHRA AND PERHAPS A MODERATE
THUNDERSTORM OR TWO ACROSS THE FHILLS AND MTNS. MAX TEMPS SHOULD
STILL BE A COUPLE DEGREES BELOW NORMAL WITH THE NE/LY SFC FLOW AND
AIRMASS MIXING.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 200 PM EDT TUESDAY...THE SHORT TERM WILL BE DOMINATED BY
SURFACE HIGH PRESSURE THAT WILL SET UP CAMP OFF THE NEW ENGLAND
COAST WHICH WILL REMAIN RIDGED SWD INTO THE SOUTHERN APPALACHIANS
THROUGH FRI. THE UPPER AIR PATTERN WILL BE ALMOST INDETERMINATE IN
THE DEEP SOUTH WITH VERY WEAK FLOW. THE AREA WILL BE BETWEEN A
TROUGH WELL TO THE NE AND AN UPPER RIDGE OVER THE SOUTHERN PLAINS.
HENCE...NO SIGNIFCANT UPPER FORCING IS ANTICIPATED. MODEL TIME
HEIGHTS INDICATE THAT MOISTURE WILL REMAIN RELATIVELY HIGH IN THE
BOUNDARY LAYER WITH DRYING ESSENTAILLY ABOVE 10KFT THROUGH THU NIGHT.
HOWEVER...MOISTURE IN THE COLUMN IS FORECAST TO DECREASE ON FRI.
HENCE...THE WEATHER SHOULD BE DRIVEN BY MAINLY BY THE LOW LEVEL WIND
FLOW AND ANY MECHANICAL LIFT IT MUSTERS...PLUS DIURNAL HEATING.
THEREFORE...MAINLY DIURNAL/SCATTERED CONVECTION IS EXPECTED PRIMARILY
OVER THE MOUNTAINS...WITH PERHAPS A DOWN TICK IN COVERAGE ON FRI
AFTERNOON DUE TO THE DRYER AIR. WITH THE WEAK UPSLOPE FLOW...SOME
NOCTURNAL WIDELY SCATTERED SHOWERS WILL REMAIN POSSIBLE OVER THE
MOUNTAINS WED/THU NIGHTS. USED AN ALLBLEND APPROACH TO TEMPERATURES
WHICH PRODUCED MAX TEMPS ON THU AND FRI ABOUT A CATEGORY BELOW
AVERAGE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 2 PM TUESDAY...THE MAIN FEATURE FOR THE EXTENDED PERIOD IS A
RIDGE OF HIGH PRESSURE THAT WILL SET UP OVER THE SOUTHEASTERN CONUS
OVER THE WEEKEND AND INTO MONDAY. THE BERMUDA HIGH WILL REMAIN
SITUATED OVER THE ATLANTIC OFF THE EAST COAST...SETTING UP A MOIST
SOUTHEASTERLY TO SOUTHWESTERLY LOW-LEVEL FLOW REGIME FOR THE REGION.
THIS WILL DRIVE MAINLY DIURNAL CONVECTION FOR THE PERIOD...WITH
GREATER CHANCE POPS FAVORING THE HIGHER ELEVATIONS EACH AFTERNOON
THROUGH THE MIDDLE OF NEXT WEEK. THE PERSISTENT RIDGE WILL ALLOW FOR
A SLIGHT WARMING TREND...WITH TEMPS NEAR TO SLIGHTLY ABOVE AVERAGE
BY THE END OF THE EXTENDED PERIOD.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
AT KCLT...THE UPPER S/W ENERGY IS BEGINNING TO INTERACT WITH
INCREASING INSTABILITY TO THE WEST OF THE TERMINAL AND THIS SHOULD
PRODUCE SOME DEEPER CELLS AND TSTMS ACROSS THE UPSTATE WITHIN THE
NEXT COUPLE HRS. THE UPPER WAVE WILL BE PROGRESSIVE AND SHOULD SWING
THIS ACTIVITY INTO THE KCLT AREA ARND 21Z...A COUPLE HRS FASTER THAN
THE MESOMODELS INDICATE. WILL TEMPO THIS IN AND EXPECT MAINLY -SHRA
IN THE VICINITY AFT 01Z. WITH THE PRECIP TODAY AND POSSIBLY THIS
EVENING...WILL INCLUDE MVFR FG FOR A FEW HRS NEAR DAYBREAK EVEN WITH
A MIX OF A LOWER T/TD AIRMASS.
ELSEWHERE...STARTING TO SEE THE CONV ACTIVITY TO THE WEST INCREASE
IN COVERAGE AND INTENSITY..WHILE A ULVL WAVE WILL PUSH ALL THIS
EAST THROUGH THE OVERNIGHT. EXPECT PERIODIC THUNDER AT ALL SITES
BEGINNING AFT 18Z OR SO AND CONTINUING THROUGH THE EARLY EVENING.
WILL COVER REMAINING LOW END ACTIVITY BEFORE THE COLD FRONT CROSSES
WITH VCSH/S. ALL SITES SHOULD SEE RESTRICTIVE VSBY OR CIGS IN THE
MVFR RANGE AROUND DAYBREAK...WITH KAVL LIKELY EXPERIENCING IFR
CONDS.
OUTLOOK...A MODERATELY UNSTABLE ATMOSPHERE COMBINED WITH EASTERLY
FLOW MAY LEAD TO SHOWER AND THUNDERSTORM DEVELOPMENT
MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% MED 63% HIGH 81%
KGSP HIGH 99% HIGH 91% MED 79% MED 70%
KAVL HIGH 96% HIGH 92% HIGH 82% HIGH 80%
KHKY HIGH 98% HIGH 100% HIGH 80% MED 69%
KGMU HIGH 100% HIGH 100% LOW 47% MED 67%
KAND HIGH 99% HIGH 99% MED 72% HIGH 91%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...VISIN
NEAR TERM...SBK
SHORT TERM...LG
LONG TERM...VISIN
AVIATION...SBK
000
FXUS62 KCAE 181801
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
201 PM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK LOW PRESSURE CONTINUES TO TRACK EASTWARD WITH A FRONTAL
BOUNDARY APPROACHING THE FORECAST AREA FROM THE NORTHWEST. VISIBLE
SATELLITE IMAGERY SHOWS SOME BREAKS IN THE OVER THE FORECAST AREA
WITH SCATTERED SHOWERS AND THUNDERSTORMS CURRENTLY APPROACHING THE
AUGUSTA AREA. EXPECT THE SHOWER AND THUNDERSTORM COVERAGE TO
INCREASE THROUGH THE AFTERNOON HOURS DUE TO THE DIURNAL HEATING
AND APPROACHING FRONT. MAIN CONCERN WITH THUNDERSTORMS REMAINS THE
POTENTIAL FOR HEAVY RAIN AS PWAT VALUES REMAIN AROUND 2 INCHES
FROM THE AFTERNOON THROUGH THE OVERNIGHT HOURS. FRONT WILL BE OVER
THE EASTERN PORTION OF THE FORECAST AREA BY DAYBREAK WITH SLIGHTLY
DRIER AIR BEGINNING TO MOVE INTO THE MID LEVELS. WITH CLOUDS
PERSISTING OVERNIGHT EXPECT LOW TEMPERATURES AROUND 70.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
UPPER TROUGH OVER THE REGION WEDNESDAY MOVES EAST BY THURSDAY AS
UPPER RIDGE STRENGTHENS OUT WEST BY THURSDAY NIGHT. SHORT WAVE DRAGS
A WEAK COLD FRONT THROUGH THE REGION WEDNESDAY. THE FRONT MOVES TO
THE SOUTH WEDNESDAY NIGHT AND ANOTHER QUITE WEAK SHORT WAVE DROPS
SOUTHWARD THURSDAY AND THURSDAY NIGHT. PLAN ON A 20-30 PERCENT CHANCE
OF SHOWERS AND THUNDERSTORMS WEDNESDAY AND A 20 PERCENT CHANCE
THURSDAY. EXPECT DIURNAL MAINLY LATE AFTERNOON AND EARLY EVENING
CONVECTIVE ACTIVITY. ALTHOUGH CAE AREA NOT OUTLOOKED FOR SEVERE
STORMS WEDNESDAY AFTERNOON...AFTERNOON SURFACE HEATING WITH TEMPERATURES
IN THE UPPER 80S TO NEAR 90 COULD CAUSE STEEPENING LAPSE RATES AND
CAUSE A FEW STRONG THUNDERSTORMS TO DEVELOP. ATMOSPHERE IS A
LITTLE DRIER WITH PWAT VALUES DOWN FROM 2.0 INCHES TODAY TO ABOUT
1.5 INCHES ON WEDNESDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT AS EAST COAST UPPER TROUGH
FRIDAY EXITS TO THE EAST AND UPPER RIDGE BUILDS ACROSS THE REGION
SATURDAY THROUGH TUESDAY. WITH UPPER RIDGE IN THE VICINITY...
TEMPERATURES SHOULD ON THE RISE. HIGHS UPPER 80S FRIDAY WILL
INCREASE TO THE LOWER 90S BY MONDAY AND TUESDAY. OVERNIGHT LOWS
ARE EXPECTED TO BE IN THE UPPER 60S TO AROUND 70. MAINLY DIURNAL
CONVECTIVE ACTIVITY DURING THE PERIOD AS EXPECT A SLIGHT CHANCE
OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. SO...FAIRLY
TYPICAL SUMMER-LIKE CONDITIONS AS THE SUMMER SOLSTICE APPROACHES.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
MIX OF VFR AND MVFR EXPECTED THROUGH THE PERIOD.
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED SOUTH AND WEST OF THE TAF
SITES WITH IMPACTS AT AGS/DNL EXPECTED BETWEEN 18 AND 19Z.
THROUGH THE AFTERNOON HOURS THE FRONT WILL MOVE INTO THE AREA AND
GENERATE ADDITIONAL SHOWERS AND THUNDERSTORMS. HAVE INCLUDED TEMPO
GROUP FOR CAE/CUB/OGB BEGINNING AT 19Z. ACTIVITY WILL DIMINISH
WITH SUNSET...HOWEVER WITH THE FRONT ACROSS THE REGION SOME
SHOWERS WILL LINGER INTO THE OVERNIGHT. NEXT CONCERN IS POTENTIAL
FOR STRATUS AND FOG AFTER 19/06Z...HAVE INCLUDED MVFR FOR AGS/OGB
DURING THE EARLY MORNING AND SUNRISE HOURS. WITH SLIGHTLY DRIER
AIR MOVING IN FOG AND STRATUS WHICH DOES DEVELOP WILL ERODE
QUICKLY WITH CONDITIONS FROM 19/13Z THROUGH THE REMAINDER OF THE
PERIOD EXPECTED VFR.
NOTE...AGS ASOS HAS BEEN RETURNED TO SERVICE.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS...AS WELL AS LATE NIGHT/EARLY MORNING FOG AND STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 181756
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
156 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE AREA TODAY THROUGH
TONIGHT. ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE REGION ON
WEDNESDAY...BUT WITH SOME DRYING OF THE ATMOSPHERE. HIGH PRESSURE
WILL BUILD OVER THE REGION THURSDAY THROUGH THE WEEKEND...BUT WITH
LOW LEVEL MOISTURE PERSISTING.
&&
.NEAR TERM /THROUGH TONIGHT/...
130 PM EDT UPDATE...STARTING TO SEE ENHANCED CONV TO THE WEST AS
THE BEST INSTABILITY INTERACTS WITH THE APPROACHING S/W. WILL
ANTICIPATE THIS TO DEVELOP MORESO INTO THE WRN ZONES OVER THE NEXT
COUPLE HRS. CURRENT POPS HAVE THIS WELL IN HAND. MADE SOME CHANGES
TO THE WIND GRIDS...ACCOUNTING FOR SOME LOW ENDS GUSTS ACROSS THE
UPSTATE AND VRB CONDS IN THE HIGHER TERRAIN.
1030 AM EDT UPDATE...CURRENT RADAR IS SHOWING A BAND OF MODERATE
RAIN SHOWERS MOVING EAST ACROSS THE UPSTATE WITH RAINFALL RATES ON
THE ORDER OF 0.5/0.75 INCHES AN HOUR PER LOCAL RAIN GAUGES. THIS
SHOULDN/T CREATE ANY FLOOD CONCERNS AS THE WHOLE SYSTEM IS MOVING
ENE AT AROUND 25 KTS. KEEPING AN EYE ON NRN GREENVILLE CO AS 3-4
INCHES OF FLOODING RAIN FELL THERE LATE LAST NIGHT...HOWEVER THE
ADDITIONAL RAIN AMOUNTS ARE NOT THREATENING ATTM. MADE SOME MINOR
CHANGES TO THE T/TD GRIDS AND MAX TEMPS STILL LOOK GOOD...ABOUT 5
DEGREES BELOW NORMAL AS A SLOW WARMING ENSUES IN A VERY MOIST
ENVIRONMENT. HIGH AMOUNTS OF SBCIN IN THE WAKE OF THESE SHOWERS WILL
LIMIT AFTERNOON CONVECTION CHANCES...SO MAY LOOK INTO REDUCING TSTM
COVERAGE FOR THE AFTERNOON/EVENING.
AS OF 350 AM EDT TUESDAY...UPPER LEVEL CYCLONIC FLOW CONTINUES TO
PROMOTE A RATHER DESTABILIZED WEATHER PATTERN ACROSS NORTHEAST
GEORGIA AND THE CAROLINAS IN THE NEAR TERM. MEANWHILE...INCREASINGLY
AMPLIFIED SHORTWAVE TROF CONTINUES ITS EASTWARD MOVEMENT ACROSS THE
MIDSOUTH REGION. IN RESPONSE...FALLING HEIGHTS AND AMPLE SURFACE
MOISTURE HAVE ALLOWED FOR CONVECTION TO REMAIN ONGOING ACROSS
PORTIONS OF MIDDLE TENNESSEE AND NORTH CENTRAL ALABAMA. EXPECTING
THIS CONVECTION TO CONTINUE ACROSS NORTHERN GEORGIA AND EAST
TENNESSEE EVENTUALLY MAKING IT ACROSS THE MOUNTAINS INTO THE CWFA.
INTO THE LATE MORNING HOURS AS THE UPPER IMPULSE SWINGS THROUGH.
KEPT CATEGORICAL POPS ACROSS THE MAJORITY OF THE FORECAST AREA
BEGINNING MID MORNING THROUGH TUESDAY AFTERNOON. BEYOND
THAT...TAPERED TO LIKELY POPS ACROSS PORTIONS OF THE UPSTATE AND THE
NORTH CAROLINA PIEDMONT. KEPT CATEGORICAL POPS ACROSS THE HIGHER
TERRAIN AS COLD FRONT WILL BE PUSHING IN AT THAT TIME. CONVERGENCE
ALONG THE FRONT AND SOME MILD INSTABILITY WILL AT LEAST PROVIDE SOME
CHANCE FOR SOME THUNDERSTORM ORGANIZATION. SHEAR PROFILES WILL
INCREASE ALONG THE FRONT THUS LEADING TO THE STRONGEST STORMS OF THE
DAY BEING IN THAT VICINITY. A COMBINATION OF SHOWER AND
THUNDERSTORM ACTIVITY FROM BOTH THE EARLIER PASSING SHORTWAVE AND
THE ENCROACHING COLD FRONT...WILL LEAD TO POTENTIAL FLASH FLOODING.
FORECAST SOUNDINGS INDICATE PWAT VALUE IN EXCESS OF 1.5 INCHES IN
SOME PLACES. THUS...ANY TRAINING THAT DEVELOPS COULD PROVIDE ENOUGH
RAINFALL IN A SHORT PERIOD OF TIME TO INITIATE FLASH FLOODING.
HOWEVER...THINK THAT IF THIS OCCURS IT WILL BE ON A MORE LOCAL SCALE
AND NOT WIDESPREAD THEREFORE OPTED AGAINST ISSUANCE OF FLASH FLOOD
WATCH. CONDITIONS SHOULD IMPROVE SOMEWHAT BEHIND THE FRONT ON
TUESDAY EVENING AS DRIER AIR SPILLS INTO THE REGION. TEMPERATURES
DURING THE NEAR TERM PERIOD WILL BE A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE TO NEAR NORMAL FOR LOWS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3200 PM EDT TUESDAY...THE SHORT TERM WILL BE DOMINATED BY HIGH
PRESSURE THAT WILL SET UP CAMP OFF THE NEW ENGLAND COAST AND WIL
REMAIN RIDGED SE INTO THE SOUTHERN APPALACHIANS THROUGH FRI. THE
UPPER AIR PATTERN WILL BE ALMOST INDETERMINATE AS WITH THE AREA
BETWENN A TROUGH WELL TO THE NE AND AN UPPER RIDGE OVER THE SOUTHERN
PLAINS. SO NO SIGNIFCANT UPPER FORCING IS ANTICIPATED. MODEL TIEM
HEIGHTS INDICATE THAT MOISTURE WIL REMAIN RELATIVELY HIGH IN THE
BOUNDARY LAYER WITH DRYING AB OVE 10KFT. MOISTURE IN THE COLUMN IS
FORECAST TO DECREASE ON FRI. HENCE...THE WEATHER SHOULD BE DRIVEN BY
MAINLTY LOW LEVEL WIND FLOW AND DIURNAL HEATING. THEREFORE...DIURNAL
CONVECTION IS EXPECTED PRIMARILY OVER THE MOUNTAINS...PERHAPS WITH A
DOWN TICK IN COVERAGE ON FRI DUE TO THE DRYER AIR. WITH THE WEAK
UPSLOPE FLOW...SOME NOCTURNAL SHOWERS WILL REMAIN POSSIBLE OVER THE
MOUNTAINS. USED AN ALLBLEND APPROACH TO TEMPERATURES WHICH PRODUCED
MAX TEMPS ON TU AND FRI ABOUT A CATEGORY BELOW AVERAGE.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM EDT TUESDAY...A DOMINANT RIDGE WILL GRADUALLY SET UP
OVER THE SOUTHEAST THROUGH THE MEDIUM RANGE PERIOD. BOUNDARY LAYER
MOISTURE WILL PERSIST FRI THROUGH MON AS BERMUDA HIGH PRESSURE
PUSHES ATLANTIC AND GULF MOISTURE INTO THE REGION ON PERSISTENT SE
TO SW LOW LEVEL FLOW. A PATTERN OF MAINLY DIURNAL CONVECTION WILL BE
ADVERTISED...WITH THE BEST CHANCE POPS OVER THE MOUNTAINS EACH
AFTERNOON AND EVENING. EXPECT A WARMING TREND UNDER THE HIGH
PRESSURE...WITH MAX TEMPS RECOVERING TO AROUND OR SLIGHTLY ABOVE
NORMAL SUNDAY AND MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...THE UPPER S/W ENERGY IS BEGINNING TO INTERACT WITH
INCREASING INSTABILITY TO THE WEST OF THE TERMINAL AND THIS SHOULD
PRODUCE SOME DEEPER CELLS AND TSTMS ACROSS THE UPSTATE WITHIN THE
NEXT COUPLE HRS. THE UPPER WAVE WILL BE PROGRESSIVE AND SHOULD SWING
THIS ACTIVITY INTO THE KCLT AREA ARND 21Z...A COUPLE HRS FASTER THAN
THE MESOMODELS INDICATE. WILL TEMPO THIS IN AND EXPECT MAINLY -SHRA
IN THE VICINITY AFT 01Z. WITH THE PRECIP TODAY AND POSSIBLY THIS
EVENING...WILL INCLUDE MVFR FG FOR A FEW HRS NEAR DAYBREAK EVEN WITH
A MIX OF A LOWER T/TD AIRMASS.
ELSEWHERE...STARTING TO SEE THE CONV ACTIVITY TO THE WEST INCREASE
IN COVERAGE AND INTENSITY..WHILE A ULVL WAVE WILL PUSH ALL THIS
EAST THROUGH THE OVERNIGHT. EXPECT PERIODIC THUNDER AT ALL SITES
BEGINNING AFT 18Z OR SO AND CONTINUING THROUGH THE EARLY EVENING.
WILL COVER REMAINING LOW END ACTIVITY BEFORE THE COLD FRONT CROSSES
WITH VCSH/S. ALL SITES SHOULD SEE RESTRICTIVE VSBY OR CIGS IN THE
MVFR RANGE AROUND DAYBREAK...WITH KAVL LIKELY EXPERIENCING IFR
CONDS.
OUTLOOK...A MODERATELY UNSTABLE ATMOSPHERE COMBINED WITH EASTERLY
FLOW MAY LEAD TO SHOWER AND THUNDERSTORM DEVELOPMENT
MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% MED 63% HIGH 81%
KGSP HIGH 99% HIGH 91% MED 79% MED 70%
KAVL HIGH 96% HIGH 92% HIGH 82% HIGH 80%
KHKY HIGH 98% HIGH 100% HIGH 80% MED 69%
KGMU HIGH 100% HIGH 100% LOW 47% MED 67%
KAND HIGH 99% HIGH 99% MED 72% HIGH 91%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG/SBK
SHORT TERM...HG
LONG TERM...HG
AVIATION...SBK
000
FXUS62 KCAE 181741
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
141 PM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...WEAK FRONTAL BOUNDARY REMAINS NORTHWEST OF THE FORECAST
AREA WITH WSR-88D RETURNS SHOWING SCATTERED SHOWERS OVER THE
CENTRAL MIDLANDS THROUGH THE CSRA. WITH SOME CLEARING ALLOWING
TEMPERATURES TO RISE INTO THE LOWER 80S EXPECT SHOWERS TO INCREASE
IN COVERAGE OVER THE NEXT COUPLE OF HOURS. MAIN CONCERN REMAINS
POTENTIAL FOR HEAVY RAIN THIS AFTERNOON AS PWAT VALUES WILL AGAIN
BE AROUND 2 INCHES. HAVE INCREASED POPS TO ACCOUNT FOR CURRENT
RADAR RETURNS AND ADJUSTED TEMPERATURES UP A DEGREE OR TWO.
PREVIOUS DISCUSSION...HIGH MOISTURE WILL CONTINUE TODAY AHEAD OF
THE SLOW MOVING FRONT. CONVERGENCE ASSOCIATED WITH THE
FRONT...HEATING...PLUS ANOTHER IN A SERIES OF MID-LEVEL SHORTWAVE
TROUGHS WILL SUPPORT NUMEROUS SHOWERS AND THUNDERSTORMS.
RADAR TRENDS INDICATE THE BATCH OF THUNDERSTORMS IN WESTERN GEORGIA
EARLY THIS MORNING WILL REACH THE WEST PART OF THE FORECAST AREA
AROUND 14Z. THE SPC WRF DISPLAYS THESE THUNDERSTORMS MOVING
THROUGH MOST OF THE FORECAST AREA DURING THE 16Z TO 20Z TIME
FRAME.
PRECIPITABLE WATER AROUND 2 INCHES AND POSSIBLE TRAINING SUPPORTS
VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS. LOCALIZED FLOODING
WILL BE POSSIBLE. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
DISPLAYS SURFACE-BASED LI/S -3 TO -4 TODAY AND THIS WEAK
INSTABILITY APPEARS REASONABLE BECAUSE OF THE CLOUDINESS AND
NUMEROUS SHOWERS. HOWEVER...THE MODELS AND ESPECIALLY THE GFS
SHOW SIGNIFICANT SHEAR. THE NAM DISPLAYS H85 WIND INCREASING TO
25 TO 30 KNOTS...THE ECMWF 30 TO 35 KNOTS...AND THE GFS 35 TO 40
KNOTS. HEAVY PRECIPITATION LOADING AND THE SHEAR SUPPORTS
ORGANIZED THUNDERSTORMS WITH DAMAGING WIND POSSIBLE.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BECAUSE OF
CLOUDINESS TODAY. USED AN AVERAGE OF THE NAM AND GFS FOR THE WIND
FORECAST.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
UPPER TROUGH OVER THE REGION WEDNESDAY MOVES EAST BY THURSDAY AS
UPPER RIDGE STRENGTHENS OUT WEST BY THURSDAY NIGHT. SHORT WAVE DRAGS
A WEAK COLD FRONT THROUGH THE REGION WEDNESDAY. THE FRONT MOVES TO
THE SOUTH WEDNESDAY NIGHT AND ANOTHER QUITE WEAK SHORT WAVE DROPS
SOUTHWARD THURSDAY AND THURSDAY NIGHT. PLAN ON A 20-30 PERCENT CHANCE
OF SHOWERS AND THUNDERSTORMS WEDNESDAY AND A 20 PERCENT CHANCE
THURSDAY. EXPECT DIURNAL MAINLY LATE AFTERNOON AND EARLY EVENING
CONVECTIVE ACTIVITY. ALTHOUGH CAE AREA NOT OUTLOOKED FOR SEVERE
STORMS WEDNESDAY AFTERNOON...AFTERNOON SURFACE HEATING WITH TEMPERATURES
IN THE UPPER 80S TO NEAR 90 COULD CAUSE STEEPENING LAPSE RATES AND
CAUSE A FEW STRONG THUNDERSTORMS TO DEVELOP. ATMOSPHERE IS A
LITTLE DRIER WITH PWAT VALUES DOWN FROM 2.0 INCHES TODAY TO ABOUT
1.5 INCHES ON WEDNESDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT AS EAST COAST UPPER TROUGH
FRIDAY EXITS TO THE EAST AND UPPER RIDGE BUILDS ACROSS THE REGION
SATURDAY THROUGH TUESDAY. WITH UPPER RIDGE IN THE VICINITY...
TEMPERATURES SHOULD ON THE RISE. HIGHS UPPER 80S FRIDAY WILL
INCREASE TO THE LOWER 90S BY MONDAY AND TUESDAY. OVERNIGHT LOWS
ARE EXPECTED TO BE IN THE UPPER 60S TO AROUND 70. MAINLY DIURNAL
CONVECTIVE ACTIVITY DURING THE PERIOD AS EXPECT A SLIGHT CHANCE
OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. SO...FAIRLY
TYPICAL SUMMERLIKE CONDITIONS AS THE SUMMER SOLSTICE APPROACHES.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
MIX OF VFR AND MVFR EXPECTED THROUGH THE PERIOD.
WEAK LOW PRESSURE AND FRONTAL BOUNDARY WILL CONTINUE TO PROGRESS
EASTWARD AND WILL IMPACT THE TAF SITES WITH SHOWERS AND
THUNDERSTORMS LATE THIS MORNING INTO THE OVERNIGHT HOURS.
SATELLITE IMAGERY SHOWS SOME DEVELOPING CUMULUS ACROSS THE
SOUTHERN MIDLANDS AND CSRA WITH RADAR RETURNS SHOWING SCATTERED
SHOWERS ALONG AND SOUTH OF CAE/CUB. EXPECT SHOWERS AND
THUNDERSTORMS TO INCREASE IN COVERAGE AND IMPACT THE TAF
SITES...HAVE REMAINED WITH VCTS FOR THE AFTERNOON HOURS AND WILL
UPDATE AS CONFIDENCE IN TIMING INCREASES. CONVECTIVE ACTIVITY WILL
DIMINISH WITH SUNSET...HOWEVER WITH THE FRONT ACROSS THE REGION
SOME SHOWERS WILL LINGER INTO THE OVERNIGHT. POTENTIAL FOR STRATUS
AND FOG AFTER 19/06Z...HOWEVER MUCH WILL DEPEND ON TIMING OF THE
FRONT SO WILL LEAVE OUT OF TAFS ATTM.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 05Z-11Z. NO TAF AMENDMENTS ARE SCHEDULED FOR AGS DURING
THAT TIME. AVIATION INTERESTS ARE ADVISED THAT AGS TENDS TO BE A FOG
PRONE LOCATION...ALSO OFTEN EXPERIENCING VARIABLE CONDITIONS.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS...AS WELL AS LATE NIGHT/EARLY MORNING FOG AND STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 181718
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
118 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY...THEN SLOWLY
PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH PRESSURE
WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND SETTLE OVER
THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NVA IN WAKE OF THE EARLY MORNING CONVECTION HAS BEEN REPLACED BY
INCREASING PVA THIS AFTERNOON AND EVENING...AS A DECENT SHORT WAVE
CROSSING THE SOUTHERN APPALACHIANS SWEEPS THROUGH. WITH VARIOUS
OUTFLOWS BOUNDARIES FROM CONVECTION UPSTREAM...DIFFERENTIAL
HEATING BOUNDARIES FROM CLOUD COVER AND LAKE BREEZES AND THE
RESULTANT SEA BREEZE...COVERAGE WILL BECOME ENHANCED FOR THE MID
AND LATE AFTERNOON. THIS OCCURS IN SYNC WITH THE MID LEVEL
IMPULSE...AIDED FURTHER BY THE CLOSE PROXIMITY TO A COUPLED UPPER
JET STRUCTURE IN EASTERN TN AND WESTERN NC TO PROVIDE ADDITIONAL
FORCING FOR ASCENT. WE CONTINUE WITH THE LIKELY POPS...AND HAVE
MAINTAINED A VERY SHARP GRADIENT FROM 20-30 POPS FROM MCINTOSH
COUNTY TO 60-70 POPS MOST ELSEWHERE.
PWATS WILL BE AS HIGH AS 1.8 TO 2.0 INCHES...SUPPORTIVE OF LOCALLY
HEAVY RAINFALL IN POTENTIAL TRAINING OF STORMS. ADDITIONALLY...THE
SEVERE RISK LOOKS TO BE THERE GIVEN THE UPPER AIR SUPPORT AND
NUMEROUS MESO-SCALE BOUNDARY INTERACTIONS TO ENHANCE THE STRENGTH
OF THE UPDRAFTS. MODIFYING THE 12Z KCHS SOUNDING...VARIOUS
THERMODYNAMIC PARAMETERS ARE SUGGESTING AT LEAST A LOW-END SEVERE
RISK. MOST NOTABLY IS THE LIFTED INDEX OF -8C...0-3 KM CAPE OF 150
J/KG OR HIGHER AND SBCAPE CLOSE TO 3000 J/KG. THE K-INDEX IS ALSO
CLOSE TO 40 AND OUR 500 MB TEMPS ARE A TAD COOLER AT -10C. PLUS
OUR MID LEVEL LAPSE RATES ARE A LITTLE MORE CONDUCIVE THAN
YESTERDAY FOR STRONGER UPDRAFTS AT -6C. MICRO-BURSTS WOULD SEEM
THE MOST LIKELY WEATHER HAZARD WITH DCAPES OF 600-1000 J/KG...PLUS
SOUNDINGS SHOWING SOME MID LEVEL DRY AIR.
DESPITE EXTENSIVE CUMULIFORM CLOUDINESS AND SOME MID/HIGHER CLOUDS
FROM UPSTREAM CONVECTION...WARM ADVECTION...A SLIGHT DOWNSLOPE
COMPONENT OFF THE MOUNTAINS THROUGHOUT A GOOD PORTION OF THE
TROPOSPHERE AND SOME COMPRESSIONAL HEATING IN ADVANCE OF A COLD
FRONT NEAR THE APPALACHIAN CHAIN...TEMPS WILL MAX OUT IN THE UPPER
80S AND LOWER 90S FOR THE VAST MAJORITY OF THE FORECAST REGION.
HOWEVER...RAIN-COOLED CONDITIONS WILL CAUSE HAVOC WITH OUR
PROJECTED TEMP CURVE AND WE HAVE MADE SOME ADJUSTMENTS TO SHOW
TEMPS FALLING THE AFTER 3 OR 4 PM IN MANY LOCATIONS. EVEN
SO...FURTHER ADJUSTMENTS WILL LIKELY BE REQUIRED IN SUBSEQUENT
UPDATES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...SHOWER/TSTM ACTIVITY WILL LINGER INTO THE NIGHT AS A
COLD FRONT MEANDERS CLOSER TO THE REGION. THE FRONT LOOKS TO
REMAIN TO THE WEST PRIOR TO SUNRISE...KEEPING THE AREA WELL WITHIN
THE WARM SECTOR. WEAK IMPULSES/VORTICITY LOBES WILL LIKELY KEEP
AT LEAST SCATTERED ACTIVITY GOING FOR MUCH OF THE NIGHT...ALTHOUGH
IDENTIFYING THE AREAS WHERE POCKETS OF CONVECTION WILL OCCUR IS
PROVING DIFFICULT. WILL KEEP CHANCE POPS GOING ALL NIGHT. LOWS
WILL RANGE FROM THE LOWER 70S INLAND TO THE MID 70S AT THE COAST.
WEDNESDAY...THE WAVE OF LOW PRESSURE RIDING ALONG THE COLD FRONT
WILL HAVE SHIFTED OFF THE MID ATLANTIC COASTLINE BY
DAYBREAK...WHILE THE MAIN SHORTWAVE RAPIDLY PROGRESSES TOWARD THE
EAST COAST AND PUSHES THE FRONT INTO THE FORECAST AREA. THE
COMBINATION OF UPPER LEVEL FORCING WITH FRONTAL CONVERGENCE WILL
SUPPORT SOLID THUNDERSTORM CHANCES UP TO 50 PERCENT DURING THE
DAYTIME HOURS...BEFORE THE FRONT SLIPS FARTHER SOUTH/SOUTHEAST AND
PULLS DEEPEST MOISTURE TOWARD THE ALTAMAHA RIVER AFTER SUNSET.
HIGHER RAIN CHANCES WERE CONSIDERED...YET FAIRLY SIGNIFICANT
TIMING DISCREPANCIES REGARDING THE PROGRESSION OF THE FRONT IS
EVIDENT BETWEEN MODELS...LENDING SOME UNCERTAINTY TO COVERAGE
DETAILS. WILL TREND CONVECTIVE POTENTIAL DOWNWARD FROM NORTH TO
SOUTH OVERNIGHT...WHILE STILL MAINTAINING 20 TO 30 PERCENT POPS
THROUGH THE PRE DAWN HOURS ON THURSDAY. INSTABILITY WILL BE
COMPROMISED BY PERSISTENT CLOUD COVER...AND WITH UNIMPRESSIVE WIND
PROFILES...THE MAIN HAZARD FROM THE STRONGEST CONVECTION WILL BE
HEAVY DOWNPOURS DUE TO SLOW STORM MOTION.
THURSDAY AND FRIDAY...THE FRONT IS EXPECTED TO STALL NEAR THE
SOUTHERN BORDER OF THE FORECAST AREA AS IT BECOMES PARALLEL TO THE
FLOW ALOFT LATE IN THE WEEK. SURFACE HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE NORTH...WITH THE PATTERN EVENTUALLY
TRANSITIONING INTO AN INLAND WEDGE/COASTAL TROUGH TYPE SCENARIO.
EXPECT BEST CONVECTIVE COVERAGE TO BE FOUND ALONG AND SOUTH OF THE
STALLED FRONT DURING THE DAYTIME HOURS...WITH SHOWER/THUNDERSTORM
ACTIVITY SHIFTING MORE TOWARD THE COAST AND OFFSHORE EACH NIGHT
WITHIN COASTAL TROUGH CONVERGENCE.
HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
NORTH TO AROUND 90 DEGREES SOUTH...WITH LOCALLY COOLER CONDITIONS
ALONG THE COASTLINE. OVERNIGHT LOWS WILL TREND A FEW DEGREES
COOLER THAN EARLIER IN THE WEEK...RANGING FROM THE UPPER 60S
INLAND TO LOWER 70S COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
CONVECTION WILL CONTINUE TO FIRE IN ADVANCE OF A COLD FRONT AND
ALONG NUMEROUS MESO-SCALE BOUNDARIES...WITH ADDITIONAL FORCING FOR
ASCENT TO RESULT FROM A SHORT WAVE THAT MOVES THROUGH LATE THIS
AFTERNOON/EVENING. WE HAVE SHOWN TEMPORARY FLIGHT RESTRICTIONS
FROM TSRA INTO THE MVFR RANGE FROM 20-24Z AT BOTH SITES AS THE
SHORT WAVE MOVES THROUGH. GUSTY WINDS...HEAVY RAINS AND POSSIBLE
IFR CONDITIONS WILL ALSO OCCUR. IN WAKE OF THE SHORT WAVE THE
AIRFIELDS WILL REMAIN VFR TONIGHT...BUT THE COLD FRONT WILL
APPROACH LATE TONIGHT/WEDNESDAY MORNING AND STALL. WITH THE FRONT
CLOSE BY ADDITIONAL SHRA/TSRA WILL DEVELOP AGAIN EARLY WEDNESDAY.
FLIGHT RESTRICTIONS ARE AGAIN POSSIBLE.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS WEDNESDAY THROUGH
THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS SHRA/TSRA...MAINLY
DURING THE AFTERNOON HOURS.
&&
.MARINE...
THIS AFTERNOON...THE COASTAL REGIME WILL BE SITUATED ON THE
EXTREME NW PERIPHERY OF THE SUB-TROPICAL ATLANTIC RIDGE...WHILE A
COLD FRONT AND PRE-FRONTAL TROUGH WILL BE FOUND OVER THE INLAND
PARTS OF THE SE. SW WINDS WILL PEAK THIS AFTERNOON ENHANCED BY THE
SEA BREEZE AND A TIGHTER PRESSURE GRADIENT...TOPPING OUT AT 15 OR
15-20 KT. SEAS WILL BE A MIXTURE OF GROUND SWELL AND WIND DRIVEN
WAVES...REACHING 3-5 FT...HIGHEST ON THE OUTER GA WATERS AND OVER
AMZ350. MARINERS ARE ALERTED TO THE POTENTIAL FOR STRONG OR SEVERE
STORMS MOVING OFF THE COAST LATE IN THE DAY AND THIS EVENING.
TONIGHT...WINDS WILL PICK UP SLIGHTLY AS A COLD FRONT APPROACHES
FROM THE WEST. WINDS LOOK TO PEAK 15-20 KT OVER THE GEORGIA
OFFSHORE WATERS AND THE CHARLESTON COUNTY COASTAL WATERS WITH 15
KT ELSEWHERE OUTSIDE OF THE CHARLESTON HARBOR. SEAS WILL REMAIN
2-4 FT NEARSHORE AND 4-5 FT GEORGIA OFFSHORE WATERS...BUT MAY
FLIRT WITH 6 FT AT TIMES ABOUT 15 NM EAST OF THE CHARLESTON COUNTY
COAST. SITUATION LOOKS TO MARGINAL FOR A SECOND PERIOD SMALL CRAFT
ADVISORY...SO WILL DEFER ANY ADVISORY DECISION TO THE NEXT
FORECAST SHIFT.
WEDNESDAY THROUGH SATURDAY...A COLD FRONT WILL SLIP INTO THE
COASTAL WATERS WEDNESDAY AND LIKELY STALL NEAR THE GEORGIA MARINE
ZONES THURSDAY. SOUTHERLY WINDS EARLY WEDNESDAY WILL THUS BECOME
EAST/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY BEHIND THE DESCENDING
FRONT. A BRIEF SURGE IN NORTHEAST FLOW IS POSSIBLE THURSDAY
AFTERNOON...AS HIGH PRESSURE RAPIDLY BUILDS FROM THE NORTH AND
BRIEFLY TIGHTENS THE GRADIENT. WIND SPEEDS COULD INCREASE TO 15 TO
20 KT OVER PORTIONS OF THE WATERS AT THAT TIME...YET CONDITIONS
WILL REMAIN BELOW SMALL CRAFT ADVISORY CONDITIONS. MODERATE
EAST/NORTHEAST FLOW WILL CONTINUE INTO FRIDAY WITHIN A COASTAL
TROUGH TYPE PATTERN...BEFORE WINDS BECOME LIGHTER ON SATURDAY AS
THE CENTER OF HIGH PRESSURE SHIFTS OFFSHORE.
RIP CURRENTS...WE HAVE MAINTAINED A MODERATE RISK AT THE BEACHES
THIS AFTERNOON...DUE TO SOUTH AND SW WINDS AROUND 15 MPH AND GUSTY
AND A 2 FOOT SWELL EVERY 10 SECONDS.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...ST/WMS
LONG TERM...WMS
AVIATION...
MARINE...
000
FXUS62 KCHS 181652
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1252 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY...THEN SLOWLY
PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH PRESSURE
WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND SETTLE OVER
THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NVA IN WAKE OF THE EARLY MORNING CONVECTION HAS BEEN REPLACED BY
INCREASING PVA THIS AFTERNOON AND EVENING...AS A DECENT SHORT WAVE
CROSSING THE SOUTHERN APPALACHIANS SWEEPS THROUGH. WITH VARIOUS
OUTFLOWS BOUNDARIES FROM CONVECTION UPSTREAM...DIFFERENTIAL
HEATING BOUNDARIES FROM CLOUD COVER AND LAKE BREEZES AND THE
RESULTANT SEA BREEZE...COVERAGE WILL BECOME ENHANCED FOR THE MID
AND LATE AFTERNOON. THIS OCCURS IN SYNC WITH THE MID LEVEL
IMPULSE...AIDED FURTHER BY THE CLOSE PROXIMITY TO A COUPLED UPPER
JET STRUCTURE IN EASTERN TN AND WESTERN NC TO PROVIDE ADDITIONAL
FORCING FOR ASCENT. WE CONTINUE WITH THE LIKELY POPS...AND HAVE
MAINTAINED A VERY SHARP GRADIENT FROM 20-30 POPS FROM MCINTOSH
COUNTY TO 60-70 POPS MOST ELSEWHERE.
PWATS WILL BE AS HIGH AS 1.8 TO 2.0 INCHES...SUPPORTIVE OF LOCALLY
HEAVY RAINFALL IN POTENTIAL TRAINING OF STORMS. ADDITIONALLY...THE
SEVERE RISK LOOKS TO BE THERE GIVEN THE UPPER AIR SUPPORT AND
NUMEROUS MESO-SCALE BOUNDARY INTERACTIONS TO ENHANCE THE STRENGTH
OF THE UPDRAFTS. MODIFYING THE 12Z KCHS SOUNDING...VARIOUS
THERMODYNAMIC PARAMETERS ARE SUGGESTING AT LEAST A LOW-END SEVERE
RISK. MOST NOTABLY IS THE LIFTED INDEX OF -8C...0-3 KM CAPE OF 150
J/KG OR HIGHER AND SBCAPE CLOSE TO 3000 J/KG. THE K-INDEX IS ALSO
CLOSE TO 40 AND OUR 500 MB TEMPS ARE A TAD COOLER AT -10C. PLUS
OUR MID LEVEL LAPSE RATES ARE A LITTLE MORE CONDUCIVE THAN
YESTERDAY FOR STRONGER UPDRAFTS AT -6C. MICRO-BURSTS WOULD SEEM
THE MOST LIKELY WEATHER HAZARD WITH DCAPES OF 600-1000 J/KG...PLUS
SOUNDINGS SHOWING SOME MID LEVEL DRY AIR.
DESPITE EXTENSIVE CUMULIFORM CLOUDINESS AND SOME MID/HIGHER CLOUDS
FROM UPSTREAM CONVECTION...WARM ADVECTION...A SLIGHT DOWNSLOPE
COMPONENT OFF THE MOUNTAINS THROUGHOUT A GOOD PORTION OF THE
TROPOSPHERE AND SOME COMPRESSIONAL HEATING IN ADVANCE OF A COLD
FRONT NEAR THE APPALACHIAN CHAIN...TEMPS WILL MAX OUT IN THE UPPER
80S AND LOWER 90S FOR THE VAST MAJORITY OF THE FORECAST REGION.
HOWEVER...RAIN-COOLED CONDITIONS WILL CAUSE HAVOC WITH OUR
PROJECTED TEMP CURVE AND WE HAVE MADE SOME ADJUSTMENTS TO SHOW
TEMPS FALLING THE AFTER 3 OR 4 PM IN MANY LOCATIONS. EVEN
SO...FURTHER ADJUSTMENTS WILL LIKELY BE REQUIRED IN SUBSEQUENT
UPDATES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...SHOWER/TSTM ACTIVITY WILL LINGER INTO THE NIGHT AS A
COLD FRONT MEANDERS CLOSER TO THE REGION. THE FRONT LOOKS TO
REMAIN TO THE WEST PRIOR TO SUNRISE...KEEPING THE AREA WELL WITHIN
THE WARM SECTOR. WEAK IMPULSES/VORTICITY LOBES WILL LIKELY KEEP
AT LEAST SCATTERED ACTIVITY GOING FOR MUCH OF THE NIGHT...ALTHOUGH
IDENTIFYING THE AREAS WHERE POCKETS OF CONVECTION WILL OCCUR IS
PROVING DIFFICULT. WILL KEEP CHANCE POPS GOING ALL NIGHT. LOWS
WILL RANGE FROM THE LOWER 70S INLAND TO THE MID 70S AT THE COAST.
WEDNESDAY...THE WAVE OF LOW PRESSURE RIDING ALONG THE COLD FRONT
WILL HAVE SHIFTED OFF THE MID ATLANTIC COASTLINE BY
DAYBREAK...WHILE THE MAIN SHORTWAVE RAPIDLY PROGRESSES TOWARD THE
EAST COAST AND PUSHES THE FRONT INTO THE FORECAST AREA. THE
COMBINATION OF UPPER LEVEL FORCING WITH FRONTAL CONVERGENCE WILL
SUPPORT SOLID THUNDERSTORM CHANCES UP TO 50 PERCENT DURING THE
DAYTIME HOURS...BEFORE THE FRONT SLIPS FARTHER SOUTH/SOUTHEAST AND
PULLS DEEPEST MOISTURE TOWARD THE ALTAMAHA RIVER AFTER SUNSET.
HIGHER RAIN CHANCES WERE CONSIDERED...YET FAIRLY SIGNIFICANT
TIMING DISCREPANCIES REGARDING THE PROGRESSION OF THE FRONT IS
EVIDENT BETWEEN MODELS...LENDING SOME UNCERTAINTY TO COVERAGE
DETAILS. WILL TREND CONVECTIVE POTENTIAL DOWNWARD FROM NORTH TO
SOUTH OVERNIGHT...WHILE STILL MAINTAINING 20 TO 30 PERCENT POPS
THROUGH THE PRE DAWN HOURS ON THURSDAY. INSTABILITY WILL BE
COMPROMISED BY PERSISTENT CLOUD COVER...AND WITH UNIMPRESSIVE WIND
PROFILES...THE MAIN HAZARD FROM THE STRONGEST CONVECTION WILL BE
HEAVY DOWNPOURS DUE TO SLOW STORM MOTION.
THURSDAY AND FRIDAY...THE FRONT IS EXPECTED TO STALL NEAR THE
SOUTHERN BORDER OF THE FORECAST AREA AS IT BECOMES PARALLEL TO THE
FLOW ALOFT LATE IN THE WEEK. SURFACE HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE NORTH...WITH THE PATTERN EVENTUALLY
TRANSITIONING INTO AN INLAND WEDGE/COASTAL TROUGH TYPE SCENARIO.
EXPECT BEST CONVECTIVE COVERAGE TO BE FOUND ALONG AND SOUTH OF THE
STALLED FRONT DURING THE DAYTIME HOURS...WITH SHOWER/THUNDERSTORM
ACTIVITY SHIFTING MORE TOWARD THE COAST AND OFFSHORE EACH NIGHT
WITHIN COASTAL TROUGH CONVERGENCE.
HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
NORTH TO AROUND 90 DEGREES SOUTH...WITH LOCALLY COOLER CONDITIONS
ALONG THE COASTLINE. OVERNIGHT LOWS WILL TREND A FEW DEGREES
COOLER THAN EARLIER IN THE WEEK...RANGING FROM THE UPPER 60S
INLAND TO LOWER 70S COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR FOR MOST OF THIS MORNING WITH PROBABILITIES INCREASING FOR
SHOWERS/TSTMS AFFECTING THE TERMINALS LATER THIS MORNING INTO THE
AFTERNOON HOURS. HIGHEST PROBABILITIES FOR IMPACTS LOOK TO OCCUR
17-20Z AT KCHS AND 16-19Z AT KSAV...BUT TIMING ADJUSTMENTS WILL BE
NEEDED AS THE DAY PROGRESSES. CAPPED CONDITIONS AT MVFR FOR NOW...
BUT BRIEF BOUTS OF IFR OR LOWER VSBYS ARE POSSIBLE IN HEAVY
CONVECTIVE RAINS. THE RISK FOR SHOWER/TSTMS WILL LINGER INTO MOST
OF THE NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. ITS UNCLEAR
WHERE EXACTLY ANY LINES OF CONVECTION WILL OCCUR...SO DID NOT
INCLUDE ANY MENTION OF PCPN DURING THE NIGHT TIME HOURS.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS TUESDAY THROUGH
THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA...MAINLY DURING THE AFTERNOON HOURS.
&&
.MARINE...
THIS AFTERNOON...THE COASTAL REGIME WILL BE SITUATED ON THE
EXTREME NW PERIPHERY OF THE SUB-TROPICAL ATLANTIC RIDGE...WHILE A
COLD FRONT AND PRE-FRONTAL TROUGH WILL BE FOUND OVER THE INLAND
PARTS OF THE SE. SW WINDS WILL PEAK THIS AFTERNOON ENHANCED BY THE
SEA BREEZE AND A TIGHTER PRESSURE GRADIENT...TOPPING OUT AT 15 OR
15-20 KT. SEAS WILL BE A MIXTURE OF GROUND SWELL AND WIND DRIVEN
WAVES...REACHING 3-5 FT...HIGHEST ON THE OUTER GA WATERS AND OVER
AMZ350. MARINERS ARE ALERTED TO THE POTENTIAL FOR STRONG OR SEVERE
STORMS MOVING OFF THE COAST LATE IN THE DAY AND THIS EVENING.
TONIGHT...WINDS WILL PICK UP SLIGHTLY AS A COLD FRONT APPROACHES
FROM THE WEST. WINDS LOOK TO PEAK 15-20 KT OVER THE GEORGIA
OFFSHORE WATERS AND THE CHARLESTON COUNTY COASTAL WATERS WITH 15
KT ELSEWHERE OUTSIDE OF THE CHARLESTON HARBOR. SEAS WILL REMAIN
2-4 FT NEARSHORE AND 4-5 FT GEORGIA OFFSHORE WATERS...BUT MAY
FLIRT WITH 6 FT AT TIMES ABOUT 15 NM EAST OF THE CHARLESTON COUNTY
COAST. SITUATION LOOKS TO MARGINAL FOR A SECOND PERIOD SMALL CRAFT
ADVISORY...SO WILL DEFER ANY ADVISORY DECISION TO THE NEXT
FORECAST SHIFT.
WEDNESDAY THROUGH SATURDAY...A COLD FRONT WILL SLIP INTO THE
COASTAL WATERS WEDNESDAY AND LIKELY STALL NEAR THE GEORGIA MARINE
ZONES THURSDAY. SOUTHERLY WINDS EARLY WEDNESDAY WILL THUS BECOME
EAST/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY BEHIND THE DESCENDING
FRONT. A BRIEF SURGE IN NORTHEAST FLOW IS POSSIBLE THURSDAY
AFTERNOON...AS HIGH PRESSURE RAPIDLY BUILDS FROM THE NORTH AND
BRIEFLY TIGHTENS THE GRADIENT. WIND SPEEDS COULD INCREASE TO 15 TO
20 KT OVER PORTIONS OF THE WATERS AT THAT TIME...YET CONDITIONS
WILL REMAIN BELOW SMALL CRAFT ADVISORY CONDITIONS. MODERATE
EAST/NORTHEAST FLOW WILL CONTINUE INTO FRIDAY WITHIN A COASTAL
TROUGH TYPE PATTERN...BEFORE WINDS BECOME LIGHTER ON SATURDAY AS
THE CENTER OF HIGH PRESSURE SHIFTS OFFSHORE.
RIP CURRENTS...WE HAVE BUMPED THE RISK UP TO MODERATE TODAY. WITH
SLIGHTLY STRONGER WINDS THAN IN THE PREVIOUS FORECAST...COMBINED
WITH A 2 FOOT SWELL EVERY 10 SECONDS THE RISK APPEARS TO BE
ENHANCED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...ST/WMS
LONG TERM...WMS
AVIATION...
MARINE...
000
FXUS62 KCHS 181647
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1247 PM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY...THEN SLOWLY
PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH PRESSURE
WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND SETTLE OVER
THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NVA IN WAKE OF THE EARLY MORNING CONVECTION HAS BEEN REPLACED BY
INCREASING PVA THIS AFTERNOON AND EVENING...AS A DECENT SHORT WAVE
CROSSING THE SOUTHERN APPALACHIANS SWEEPS THROUGH. WITH VARIOUS
OUTFLOWS BOUNDARIES FROM CONVECTION UPSTREAM...DIFFERENTIAL
HEATING BOUNDARIES FROM CLOUD COVER AND LAKE BREEZES AND THE
RESULTANT SEA BREEZE...COVERAGE WILL BECOME ENHANCED FOR THE MID
AND LATE AFTERNOON. THIS OCCURS IN SYNC WITH THE MID LEVEL
IMPULSE...AIDED FURTHER BY THE CLOSE PROXIMITY TO A COUPLED UPPER
JET STRUCTURE IN EASTERN TN AND WESTERN NC TO PROVIDE ADDITIONAL
FORCING FOR ASCENT. WE CONTINUE WITH THE LIKELY POPS...AND HAVE
MAINTAINED A VERY SHARP GRADIENT FROM 20-30 POPS FROM MCINTOSH
COUNTY TO 60-70 POPS MOST ELSEWHERE.
PWATS WILL BE AS HIGH AS 1.8 TO 2.0 INCHES...SUPPORTIVE OF LOCALLY
HEAVY RAINFALL IN POTENTIAL TRAINING OF STORMS. ADDITIONALLY...THE
SEVERE RISK LOOKS TO BE THERE GIVEN THE UPPER AIR SUPPORT AND
NUMEROUS MESO-SCALE BOUNDARY INTERACTIONS TO ENHANCE THE STRENGTH
OF THE UPDRAFTS. MODIFYING THE 12Z KCHS SOUNDING...VARIOUS
THERMODYNAMIC PARAMETERS ARE SUGGESTING AT LEAST A LOW-END SEVERE
RISK. MOST NOTABLY IS THE LIFTED INDEX OF -8C...0-3 KM CAPE OF 150
J/KG OR HIGHER AND SBCAPE CLOSE TO 3000 J/KG. THE K-INDEX IS ALSO
CLOSE TO 40 AND OUR 500 MB TEMPS ARE A TAD COOLER AT -10C. PLUS
OUR MID LEVEL LAPSE RATES ARE A LITTLE MORE CONDUCIVE THAN
YESTERDAY FOR STRONGER UPDRAFTS AT -6C. WET MICRO-BURSTS WOULD
SEEM THE MOST LIKELY WEATHER HAZARD WITH DCAPES OF 600-800 J/KG.
DESPITE EXTENSIVE CUMULIFORM CLOUDINESS AND SOME MID/HIGHER CLOUDS
FROM UPSTREAM CONVECTION...WARM ADVECTION...A SLIGHT DOWNSLOPE
COMPONENT OFF THE MOUNTAINS THROUGHOUT A GOOD PORTION OF THE
TROPOSPHERE AND SOME COMPRESSIONAL HEATING IN ADVANCE OF A COLD
FRONT NEAR THE APPALACHIAN CHAIN...TEMPS WILL MAX OUT IN THE UPPER
80S AND LOWER 90S FOR THE VAST MAJORITY OF THE FORECAST REGION.
HOWEVER...RAIN-COOLED CONDITIONS WILL CAUSE HAVOC WITH OUR
PROJECTED TEMP CURVE AND WE HAVE MADE SOME ADJUSTMENTS TO SHOW
TEMPS FALLING THE AFTER 3 OR 4 PM IN MANY LOCATIONS. EVEN
SO...FURTHER ADJUSTMENTS WILL LIKELY BE REQUIRED IN SUBSEQUENT
UPDATES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...SHOWER/TSTM ACTIVITY WILL LINGER INTO THE NIGHT AS A
COLD FRONT MEANDERS CLOSER TO THE REGION. THE FRONT LOOKS TO
REMAIN TO THE WEST PRIOR TO SUNRISE...KEEPING THE AREA WELL WITHIN
THE WARM SECTOR. WEAK IMPULSES/VORTICITY LOBES WILL LIKELY KEEP
AT LEAST SCATTERED ACTIVITY GOING FOR MUCH OF THE NIGHT...ALTHOUGH
IDENTIFYING THE AREAS WHERE POCKETS OF CONVECTION WILL OCCUR IS
PROVING DIFFICULT. WILL KEEP CHANCE POPS GOING ALL NIGHT. LOWS
WILL RANGE FROM THE LOWER 70S INLAND TO THE MID 70S AT THE COAST.
WEDNESDAY...THE WAVE OF LOW PRESSURE RIDING ALONG THE COLD FRONT
WILL HAVE SHIFTED OFF THE MID ATLANTIC COASTLINE BY
DAYBREAK...WHILE THE MAIN SHORTWAVE RAPIDLY PROGRESSES TOWARD THE
EAST COAST AND PUSHES THE FRONT INTO THE FORECAST AREA. THE
COMBINATION OF UPPER LEVEL FORCING WITH FRONTAL CONVERGENCE WILL
SUPPORT SOLID THUNDERSTORM CHANCES UP TO 50 PERCENT DURING THE
DAYTIME HOURS...BEFORE THE FRONT SLIPS FARTHER SOUTH/SOUTHEAST AND
PULLS DEEPEST MOISTURE TOWARD THE ALTAMAHA RIVER AFTER SUNSET.
HIGHER RAIN CHANCES WERE CONSIDERED...YET FAIRLY SIGNIFICANT
TIMING DISCREPANCIES REGARDING THE PROGRESSION OF THE FRONT IS
EVIDENT BETWEEN MODELS...LENDING SOME UNCERTAINTY TO COVERAGE
DETAILS. WILL TREND CONVECTIVE POTENTIAL DOWNWARD FROM NORTH TO
SOUTH OVERNIGHT...WHILE STILL MAINTAINING 20 TO 30 PERCENT POPS
THROUGH THE PRE DAWN HOURS ON THURSDAY. INSTABILITY WILL BE
COMPROMISED BY PERSISTENT CLOUD COVER...AND WITH UNIMPRESSIVE WIND
PROFILES...THE MAIN HAZARD FROM THE STRONGEST CONVECTION WILL BE
HEAVY DOWNPOURS DUE TO SLOW STORM MOTION.
THURSDAY AND FRIDAY...THE FRONT IS EXPECTED TO STALL NEAR THE
SOUTHERN BORDER OF THE FORECAST AREA AS IT BECOMES PARALLEL TO THE
FLOW ALOFT LATE IN THE WEEK. SURFACE HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE NORTH...WITH THE PATTERN EVENTUALLY
TRANSITIONING INTO AN INLAND WEDGE/COASTAL TROUGH TYPE SCENARIO.
EXPECT BEST CONVECTIVE COVERAGE TO BE FOUND ALONG AND SOUTH OF THE
STALLED FRONT DURING THE DAYTIME HOURS...WITH SHOWER/THUNDERSTORM
ACTIVITY SHIFTING MORE TOWARD THE COAST AND OFFSHORE EACH NIGHT
WITHIN COASTAL TROUGH CONVERGENCE.
HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
NORTH TO AROUND 90 DEGREES SOUTH...WITH LOCALLY COOLER CONDITIONS
ALONG THE COASTLINE. OVERNIGHT LOWS WILL TREND A FEW DEGREES
COOLER THAN EARLIER IN THE WEEK...RANGING FROM THE UPPER 60S
INLAND TO LOWER 70S COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR FOR MOST OF THIS MORNING WITH PROBABILITIES INCREASING FOR
SHOWERS/TSTMS AFFECTING THE TERMINALS LATER THIS MORNING INTO THE
AFTERNOON HOURS. HIGHEST PROBABILITIES FOR IMPACTS LOOK TO OCCUR
17-20Z AT KCHS AND 16-19Z AT KSAV...BUT TIMING ADJUSTMENTS WILL BE
NEEDED AS THE DAY PROGRESSES. CAPPED CONDITIONS AT MVFR FOR NOW...
BUT BRIEF BOUTS OF IFR OR LOWER VSBYS ARE POSSIBLE IN HEAVY
CONVECTIVE RAINS. THE RISK FOR SHOWER/TSTMS WILL LINGER INTO MOST
OF THE NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. ITS UNCLEAR
WHERE EXACTLY ANY LINES OF CONVECTION WILL OCCUR...SO DID NOT
INCLUDE ANY MENTION OF PCPN DURING THE NIGHT TIME HOURS.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS TUESDAY THROUGH
THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA...MAINLY DURING THE AFTERNOON HOURS.
&&
.MARINE...
THIS AFTERNOON...THE COASTAL REGIME WILL BE SITUATED ON THE
EXTREME NW PERIPHERY OF THE SUB-TROPICAL ATLANTIC RIDGE...WHILE A
COLD FRONT AND PRE-FRONTAL TROUGH WILL BE FOUND OVER THE INLAND
PARTS OF THE SE. SW WINDS WILL PEAK THIS AFTERNOON ENHANCED BY THE
SEA BREEZE AND A TIGHTER PRESSURE GRADIENT...TOPPING OUT AT 15 OR
15-20 KT. SEAS WILL BE A MIXTURE OF GROUND SWELL AND WIND DRIVEN
WAVES...REACHING 3-5 FT...HIGHEST ON THE OUTER GA WATERS AND OVER
AMZ350. MARINERS ARE ALERTED TO THE POTENTIAL FOR STRONG OR SEVERE
STORMS MOVING OFF THE COAST LATE IN THE DAY AND THIS EVENING.
TONIGHT...WINDS WILL PICK UP SLIGHTLY AS A COLD FRONT APPROACHES
FROM THE WEST. WINDS LOOK TO PEAK 15-20 KT OVER THE GEORGIA
OFFSHORE WATERS AND THE CHARLESTON COUNTY COASTAL WATERS WITH 15
KT ELSEWHERE OUTSIDE OF THE CHARLESTON HARBOR. SEAS WILL REMAIN
2-4 FT NEARSHORE AND 4-5 FT GEORGIA OFFSHORE WATERS...BUT MAY
FLIRT WITH 6 FT AT TIMES ABOUT 15 NM EAST OF THE CHARLESTON COUNTY
COAST. SITUATION LOOKS TO MARGINAL FOR A SECOND PERIOD SMALL CRAFT
ADVISORY...SO WILL DEFER ANY ADVISORY DECISION TO THE NEXT
FORECAST SHIFT.
WEDNESDAY THROUGH SATURDAY...A COLD FRONT WILL SLIP INTO THE
COASTAL WATERS WEDNESDAY AND LIKELY STALL NEAR THE GEORGIA MARINE
ZONES THURSDAY. SOUTHERLY WINDS EARLY WEDNESDAY WILL THUS BECOME
EAST/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY BEHIND THE DESCENDING
FRONT. A BRIEF SURGE IN NORTHEAST FLOW IS POSSIBLE THURSDAY
AFTERNOON...AS HIGH PRESSURE RAPIDLY BUILDS FROM THE NORTH AND
BRIEFLY TIGHTENS THE GRADIENT. WIND SPEEDS COULD INCREASE TO 15 TO
20 KT OVER PORTIONS OF THE WATERS AT THAT TIME...YET CONDITIONS
WILL REMAIN BELOW SMALL CRAFT ADVISORY CONDITIONS. MODERATE
EAST/NORTHEAST FLOW WILL CONTINUE INTO FRIDAY WITHIN A COASTAL
TROUGH TYPE PATTERN...BEFORE WINDS BECOME LIGHTER ON SATURDAY AS
THE CENTER OF HIGH PRESSURE SHIFTS OFFSHORE.
RIP CURRENTS...WE HAVE BUMPED THE RISK UP TO MODERATE TODAY. WITH
SLIGHTLY STRONGER WINDS THAN IN THE PREVIOUS FORECAST...COMBINED
WITH A 2 FOOT SWELL EVERY 10 SECONDS THE RISK APPEARS TO BE
ENHANCED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...ST/WMS
LONG TERM...WMS
AVIATION...
MARINE...
000
FXUS62 KGSP 181431
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1031 AM EDT TUE JUN 18 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE AREA TODAY THROUGH
TONIGHT. ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE REGION ON
WEDNESDAY...BUT WITH SOME DRYING OF THE ATMOSPHERE. HIGH PRESSURE
WILL BUILD OVER THE REGION THURSDAY THROUGH THE WEEKEND...BUT WITH
LOW LEVEL MOISTURE PERSISTING.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM EDT UPDATE...CURRENT RADAR IS SHOWING A BAND OF MODERATE
RAIN SHOWERS MOVING EAST ACROSS THE UPSTATE WITH RAINFALL RATES ON
THE ORDER OF 0.5/0.75 INCHES AN HOUR PER LOCAL RAIN GAUGES. THIS
SHOULDN/T CREATE ANY FLOOD CONCERNS AS THE WHOLE SYSTEM IS MOVING
ENE AT AROUND 25 KTS. KEEPING AN EYE ON NRN GREENVILLE CO AS 3-4
INCHES OF FLOODING RAIN FELL THERE LATE LAST NIGHT...HOWEVER THE
ADDITIONAL RAIN AMOUNTS ARE NOT THREATENING ATTM. MADE SOME MINOR
CHANGES TO THE T/TD GRIDS AND MAX TEMPS STILL LOOK GOOD...ABOUT 5
DEGREES BELOW NORMAL AS A SLOW WARMING ENSUES IN A VERY MOIST
ENVIRONMENT. HIGH AMOUNTS OF SBCIN IN THE WAKE OF THESE SHOWERS WILL
LIMIT AFTERNOON CONVECTION CHANCES...SO MAY LOOK INTO REDUCING TSTM
COVERAGE FOR THE AFTERNOON/EVENING.
AS OF 350 AM EDT TUESDAY...UPPER LEVEL CYCLONIC FLOW CONTINUES TO
PROMOTE A RATHER DESTABILIZED WEATHER PATTERN ACROSS NORTHEAST
GEORGIA AND THE CAROLINAS IN THE NEAR TERM. MEANWHILE...INCREASINGLY
AMPLIFIED SHORTWAVE TROF CONTINUES ITS EASTWARD MOVEMENT ACROSS THE
MIDSOUTH REGION. IN RESPONSE...FALLING HEIGHTS AND AMPLE SURFACE
MOISTURE HAVE ALLOWED FOR CONVECTION TO REMAIN ONGOING ACROSS
PORTIONS OF MIDDLE TENNESSEE AND NORTH CENTRAL ALABAMA. EXPECTING
THIS CONVECTION TO CONTINUE ACROSS NORTHERN GEORGIA AND EAST
TENNESSEE EVENTUALLY MAKING IT ACROSS THE MOUNTAINS INTO THE CWFA.
INTO THE LATE MORNING HOURS AS THE UPPER IMPULSE SWINGS THROUGH.
KEPT CATEGORICAL POPS ACROSS THE MAJORITY OF THE FORECAST AREA
BEGINNING MID MORNING THROUGH TUESDAY AFTERNOON. BEYOND
THAT...TAPERED TO LIKELY POPS ACROSS PORTIONS OF THE UPSTATE AND THE
NORTH CAROLINA PIEDMONT. KEPT CATEGORICAL POPS ACROSS THE HIGHER
TERRAIN AS COLD FRONT WILL BE PUSHING IN AT THAT TIME. CONVERGENCE
ALONG THE FRONT AND SOME MILD INSTABILITY WILL AT LEAST PROVIDE SOME
CHANCE FOR SOME THUNDERSTORM ORGANIZATION. SHEAR PROFILES WILL
INCREASE ALONG THE FRONT THUS LEADING TO THE STRONGEST STORMS OF THE
DAY BEING IN THAT VICINITY. A COMBINATION OF SHOWER AND
THUNDERSTORM ACTIVITY FROM BOTH THE EARLIER PASSING SHORTWAVE AND
THE ENCROACHING COLD FRONT...WILL LEAD TO POTENTIAL FLASH FLOODING.
FORECAST SOUNDINGS INDICATE PWAT VALUE IN EXCESS OF 1.5 INCHES IN
SOME PLACES. THUS...ANY TRAINING THAT DEVELOPS COULD PROVIDE ENOUGH
RAINFALL IN A SHORT PERIOD OF TIME TO INITIATE FLASH FLOODING.
HOWEVER...THINK THAT IF THIS OCCURS IT WILL BE ON A MORE LOCAL SCALE
AND NOT WIDESPREAD THEREFORE OPTED AGAINST ISSUANCE OF FLASH FLOOD
WATCH. CONDITIONS SHOULD IMPROVE SOMEWHAT BEHIND THE FRONT ON
TUESDAY EVENING AS DRIER AIR SPILLS INTO THE REGION. TEMPERATURES
DURING THE NEAR TERM PERIOD WILL BE A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE TO NEAR NORMAL FOR LOWS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM EDT TUESDAY...A POSITIVE TILT CLIPPER TYPE WAVE WILL
CROSS THE FORECAST AREA WED MORNING ALONG WITH THE ENTRANCE REGION
OF A WEAK UPPER JETLET. HOWEVER...A MID LEVEL DRY PUNCH WRAPPING IN
UNDER THE PASSING WAVE WILL CONSPIRE TO LIMIT SHOWER AND TSTM
COVERAGE TO SCATTERED AT BEST...MAINLY IN THE SLIGHTLY MORE UNSTABLE
EASTERN SECTIONS. THE FORECAST MODELS THEN SHOW REDEVELOPMENT BACK
OVER THE MTNS DURING THE AFTERNOON HOURS AS BOUNDARY LAYER
CONVERGENCE INCREASES AHEAD OF A WEAK COLD FRONT SETTLING SOUTHWARD
ALONG THE APPALACHIANS. WILL EXTEND SCATTERED TSTM COVERAGE SE INTO
THE PIEDMONT THROUGH EARLY WED EVENING BEFORE THE ACTIVITY
DISSIPATES.
UPPER HEIGHTS WILL THEN INCREASE IN EARNEST WED NIGHT THROUGH THU
NIGHT. ALTHOUGH MID AND UPPER LEVELS DRY OUT DURING THIS
PERIOD...THE SFC TO 850 MB LAYER WILL REMAIN MOIST AND A SE UPSLOPE
FLOW WILL DEVELOP TO KEEP SOME CLOUDS IN THE PICTURE. WILL FEATURE
MORE OF A DIURNAL SCT MTN TO ISOLD PIEDMONT TSTM PATTERN FOR THU
AFTN AND EVENING...WITH MAX TEMPS REMAINING BELOW CLIMATOLOGY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM EDT TUESDAY...A DOMINANT RIDGE WILL GRADUALLY SET UP
OVER THE SOUTHEAST THROUGH THE MEDIUM RANGE PERIOD. BOUNDARY LAYER
MOISTURE WILL PERSIST FRI THROUGH MON AS BERMUDA HIGH PRESSURE
PUSHES ATLANTIC AND GULF MOISTURE INTO THE REGION ON PERSISTENT SE
TO SW LOW LEVEL FLOW. A PATTERN OF MAINLY DIURNAL CONVECTION WILL BE
ADVERTISED...WITH THE BEST CHANCE POPS OVER THE MOUNTAINS EACH
AFTERNOON AND EVENING. EXPECT A WARMING TREND UNDER THE HIGH
PRESSURE...WITH MAX TEMPS RECOVERING TO AROUND OR SLIGHTLY ABOVE
NORMAL SUNDAY AND MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
AT KCLT...SOLID IFR CIGS HAVE PREVAILED AT CHARLOTTE THROUGH THE
EVENING...HOWEVER STILL EXPECTING AN IMPROVEMENT TO MVFR LEVELS A
FEW HOURS AFTER SUNRISE. SCATTERED CONVECTION CONTINUES ACROSS
PORTIONS OF EAST TENNESSEE AND NORTHEAST GEORGIA ASSOCIATED WITH AN
ADVANCING SHORT WAVE TROF. AS UPPER LEVEL SHORT WAVE TROF
APPROACHES...AMPLE MOISTURE IN THE BOUNDARY LAYER WILL PROMPT A
REORGANIZATION OF OVC MVFR CIGS AND SCATTERED SHOWER DEVELOPMENT.
PRECIPITATION COVERAGE WILL CONTINUE TO INCREASE THROUGH THE LATE
MORNING HOURS ACROSS THE REGION THUS ADDED -SHRA BY AROUND 15Z.
CIGS WILL INCREASE TO VFR LEVELS LATE TOMORROW MORNING AS THE
ATMOSPHERE HEATS. FURTHERMORE...INCREASING INSTABILITY THROUGH THE
COLUMN...AND CONVERGENCE ALONG A PASSING FRONTAL BOUNDARY WILL ALLOW
FOR SOME THUNDERSTORM DEVELOPMENT TOMORROW AFTERNOON. WITH
THAT...INCLUDED A TEMPO FROM 20-24Z FOR MVFR VISB WITH TSRA. THE
FRONT WILL LIKELY NOT REACH KCLT UNTIL AROUND THE 02Z TIMEFRAME
SHIFTING WINDS TO A NORTHERLY COMPONENT. WINDS ALONG AND JUST AHEAD
OF THE FRONT COULD BE GUSTY WITH READINGS IN THE 20KT RANGE NOT
BEING OUT OF THE QUESTION.
ELSEWHERE...CIGS WILL RAISE SLIGHTLY ON TUESDAY MORNING BUT SHOULD
REMAIN AT MVFR LEVELS. CIGS WILL FINALLY REBOUND TO VFR CONDITIONS
LATE MORNING AS THE BOUNDARY LAYER WARMS. BY MID TO LATE
MORNING...UPPER LEVEL SHORTWAVE WILL MOVE IN...AND INSTABILITY WILL
HAVE INCREASED SOMEWHAT ALLOWING FOR SOME THUNDERSTORM ACTIVITY TO
DEVELOP. THE WINDOW FOR THUNDERSTORMS LOOKS TO BE A LITTLE NARROWER
FOR THE SOUTH CAROLINA SITES..THUS HANDLED THEM WITH TEMPO GROUPS.
FOR KAVL AND KHKY...DECIDED TO PREVAIL TSRA AS MODEL GUIDANCE
INDICATES INSTABILITY SHOULD REMAIN HIGHER LATER INTO THE DAY AS THE
FRONT APPROACHES. NEAR THE END OF THE PERIOD...THE FRONT WILL MOVE
THROUGH WESTERN NORTH CAROLINA BY AROUND 01Z...AND CONTINUE PUSHING
TO THE SOUTHEAST REACHING THE SOUTH CAROLINA SITES BY AROUND 03-04Z
WEDNESDAY. WINDS ALONG AND JUST AHEAD OF THE FRONT COULD BE GUSTY
WITH READINGS IN THE 20KT RANGE NOT BEING OUT OF THE QUESTION.
OUTLOOK...CONDITIONS WILL IMPROVE SOMEWHAT TUE NIGHT AS DRIER AIR
FILLS IN BEHIND A COLD FRONT. A MODERATELY UNSTABLE ATMOSPHERE
COMBINED WITH EASTERLY FLOW MAY LEAD TO SHOWER AND THUNDERSTORM
DEVELOPMENT MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 87% HIGH 98% HIGH 89% HIGH 94%
KGSP HIGH 94% HIGH 98% HIGH 95% HIGH 100%
KAVL HIGH 88% HIGH 93% HIGH 89% MED 71%
KHKY HIGH 84% HIGH 94% HIGH 92% MED 79%
KGMU HIGH 92% HIGH 98% HIGH 91% HIGH 98%
KAND HIGH 81% HIGH 97% HIGH 97% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG/SBK
SHORT TERM...HG
LONG TERM...HG
AVIATION...CDG
000
FXUS62 KCHS 181429
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1029 AM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY...THEN SLOWLY
PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH PRESSURE
WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND SETTLE OVER
THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE LATE MORNING PATTERN SHOWS THE LOCAL AREA WITH FAIRLY BENIGN
CONDITIONS...ALTHOUGH THAT WILL SOON BE CHANGING FOR THE WORST.
NVA IN WAKE OF THE EARLY MORNING CONVECTION WILL BE REPLACED BY
INCREASING PVA THIS AFTERNOON AND EVENING...AS A DECENT SHORT WAVE
NEAR THE SOUTHERN APPALACHIANS SWEEPS IN AFTER 18Z. WE/RE ALREADY
SEEING SIGNS OF ITS IMPACT WITH ISOLATED TO SCATTERED CONVECTION
JUST TO THE WEST AND NW OF THE CWFA...AND MOVING EAST AND NE
TOWARD THE LOCAL ZONES. ISOLATED TO SCATTERED SHOWERS AND
T-STORMS WILL START TO DEVELOP BY 16-17Z AS WE REACH OUR
CONVECTIVE TEMPS AND ISOLATED ACTIVITY FORMS ON THE SEA BREEZE.
WITH VARIOUS OUTFLOWS BOUNDARIES FROM CONVECTION
UPSTREAM...DIFFERENTIAL HEATING BOUNDARIES FROM CLOUD COVER IN
CENTRAL AND SOUTHERN ZONES THIS MORNING AND LAKE BREEZES AND THE
RESULTANT SEA BREEZE...COVERAGE WILL BECOME ENHANCED FOR THE MID
AND LATE AFTERNOON. THIS OCCURS IN SYNC WITH THE MID LEVEL
IMPULSE...AIDED FURTHER BY THE CLOSE PROXIMITY TO A COUPLED UPPER
JET STRUCTURE IN EASTERN TN AND WESTERN NC TO PROVIDE ADDITIONAL
FORCING FOR ASCENT. WE HAVE EXPANDED THE LIKELY POPS FURTHER
EAST...BUT HAVE MAINTAINED A VERY SHARP GRADIENT FROM 20-30 POPS
FROM MCINTOSH COUNTY TO 60-70 POPS MOST ELSEWHERE.
PWATS WILL BE AS HIGH AS 1.8 TO 2.0 INCHES...SUPPORTIVE OF LOCALLY
HEAVY RAINFALL IN POTENTIAL TRAINING OF STORMS. ADDITIONALLY...THE
SEVERE RISK LOOKS TO BE THERE GIVEN THE UPPER AIR SUPPORT AND
NUMEROUS MESO-SCALE BOUNDARY INTERACTIONS TO ENHANCE THE STRENGTH
OF THE UPDRAFTS. MODIFYING THE 12Z KCHS SOUNDING...VARIOUS
THERMODYNAMIC PARAMETERS ARE SUGGESTING AT LEAST A LOW-END SEVERE
RISK. MOST NOTABLY IS THE LIFTED INDEX OF -8C...0-3 KM CAPE OF 150
J/KG OR HIGHER AND SBCAPE CLOSE TO 3000 J/KG. THE K-INDEX IS ALSO
CLOSE TO 40 AND OUR 500 MB TEMPS ARE A TAD COOLER AT -10C. PLUS
OUR MID LEVEL LAPSE RATES ARE A LITTLE MORE CONDUCIVE THAN
YESTERDAY FOR STRONGER UPDRAFTS AT -6C. WET MICRO-BURSTS WOULD
SEEM THE MOST LIKELY WEATHER HAZARD WITH DCAPES OF 600-800 J/KG.
DESPITE THE WET GROUNDS IN MANY LOCATIONS THIS MORNING...STRONG
JUNE INSOLATION AS EVAPORATED A LOT OF THE STANDING RAINWATER AND
ALLOWED TEMPS TO CLIMB RAPIDLY. WITH A SLIGHT DOWNSLOPE COMPONENT
OFF THE MOUNTAINS THROUGHOUT A GOOD PORTION OF THE TROPOSPHERE AND
SOME COMPRESSIONAL HEATING IN ADVANCE OF A COLD FRONT NEAR THE
APPALACHIAN CHAIN...TEMPS WILL MAX OUT IN THE UPPER 80S AND LOWER
90S FOR THE VAST MAJORITY OF THE FORECAST REGION. HOWEVER...RAIN-
COOLED CONDITIONS WILL CAUSE HAVOC WITH OUR PROJECTED TEMP CURVE
TODAY AND ADJUSTMENTS WILL LIKELY BE REQUIRED IN SUBSEQUENT
UPDATES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...SHOWER/TSTM ACTIVITY WILL LINGER INTO THE NIGHT AS A
COLD FRONT MEANDERS CLOSER TO THE REGION. THE FRONT LOOKS TO
REMAIN TO THE WEST PRIOR TO SUNRISE...KEEPING THE AREA WELL WITHIN
THE WARM SECTOR. WEAK IMPULSES/VORTICITY LOBES WILL LIKELY KEEP
AT LEAST SCATTERED ACTIVITY GOING FOR MUCH OF THE NIGHT...ALTHOUGH
IDENTIFYING THE AREAS WHERE POCKETS OF CONVECTION WILL OCCUR IS
PROVING DIFFICULT. WILL KEEP CHANCE POPS GOING ALL NIGHT. LOWS
WILL RANGE FROM THE LOWER 70S INLAND TO THE MID 70S AT THE COAST.
WEDNESDAY...THE WAVE OF LOW PRESSURE RIDING ALONG THE COLD FRONT
WILL HAVE SHIFTED OFF THE MID ATLANTIC COASTLINE BY
DAYBREAK...WHILE THE MAIN SHORTWAVE RAPIDLY PROGRESSES TOWARD THE
EAST COAST AND PUSHES THE FRONT INTO THE FORECAST AREA. THE
COMBINATION OF UPPER LEVEL FORCING WITH FRONTAL CONVERGENCE WILL
SUPPORT SOLID THUNDERSTORM CHANCES UP TO 50 PERCENT DURING THE
DAYTIME HOURS...BEFORE THE FRONT SLIPS FARTHER SOUTH/SOUTHEAST AND
PULLS DEEPEST MOISTURE TOWARD THE ALTAMAHA RIVER AFTER SUNSET.
HIGHER RAIN CHANCES WERE CONSIDERED...YET FAIRLY SIGNIFICANT
TIMING DISCREPANCIES REGARDING THE PROGRESSION OF THE FRONT IS
EVIDENT BETWEEN MODELS...LENDING SOME UNCERTAINTY TO COVERAGE
DETAILS. WILL TREND CONVECTIVE POTENTIAL DOWNWARD FROM NORTH TO
SOUTH OVERNIGHT...WHILE STILL MAINTAINING 20 TO 30 PERCENT POPS
THROUGH THE PRE DAWN HOURS ON THURSDAY. INSTABILITY WILL BE
COMPROMISED BY PERSISTENT CLOUD COVER...AND WITH UNIMPRESSIVE WIND
PROFILES...THE MAIN HAZARD FROM THE STRONGEST CONVECTION WILL BE
HEAVY DOWNPOURS DUE TO SLOW STORM MOTION.
THURSDAY AND FRIDAY...THE FRONT IS EXPECTED TO STALL NEAR THE
SOUTHERN BORDER OF THE FORECAST AREA AS IT BECOMES PARALLEL TO THE
FLOW ALOFT LATE IN THE WEEK. SURFACE HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE NORTH...WITH THE PATTERN EVENTUALLY
TRANSITIONING INTO AN INLAND WEDGE/COASTAL TROUGH TYPE SCENARIO.
EXPECT BEST CONVECTIVE COVERAGE TO BE FOUND ALONG AND SOUTH OF THE
STALLED FRONT DURING THE DAYTIME HOURS...WITH SHOWER/THUNDERSTORM
ACTIVITY SHIFTING MORE TOWARD THE COAST AND OFFSHORE EACH NIGHT
WITHIN COASTAL TROUGH CONVERGENCE.
HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
NORTH TO AROUND 90 DEGREES SOUTH...WITH LOCALLY COOLER CONDITIONS
ALONG THE COASTLINE. OVERNIGHT LOWS WILL TREND A FEW DEGREES
COOLER THAN EARLIER IN THE WEEK...RANGING FROM THE UPPER 60S
INLAND TO LOWER 70S COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
VFR FOR MOST OF THIS MORNING WITH PROBABILITIES INCREASING FOR
SHOWERS/TSTMS AFFECTING THE TERMINALS LATER THIS MORNING INTO THE
AFTERNOON HOURS. HIGHEST PROBABILITIES FOR IMPACTS LOOK TO OCCUR
17-20Z AT KCHS AND 16-19Z AT KSAV...BUT TIMING ADJUSTMENTS WILL BE
NEEDED AS THE DAY PROGRESSES. CAPPED CONDITIONS AT MVFR FOR NOW...
BUT BRIEF BOUTS OF IFR OR LOWER VSBYS ARE POSSIBLE IN HEAVY
CONVECTIVE RAINS. THE RISK FOR SHOWER/TSTMS WILL LINGER INTO MOST
OF THE NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. ITS UNCLEAR
WHERE EXACTLY ANY LINES OF CONVECTION WILL OCCUR...SO DID NOT
INCLUDE ANY MENTION OF PCPN DURING THE NIGHT TIME HOURS.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS TUESDAY THROUGH
THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA...MAINLY DURING THE AFTERNOON HOURS.
&&
.MARINE...
TODAY...THE COASTAL REGIME WILL BE SITUATED ON THE EXTREME NW
PERIPHERY OF THE SUB-TROPICAL ATLANTIC RIDGE...WHILE A COLD FRONT
AND PRE-FRONTAL TROUGH WILL BE FOUND OVER THE INLAND PARTS OF THE
SE. SW WINDS WILL PEAK THIS AFTERNOON ENHANCED BY THE SEA BREEZE
AND A TIGHTER PRESSURE GRADIENT...TOPPING OUT AT 15 OR 15-20 KT.
SEAS WILL BE A MIXTURE OF GROUND SWELL AND WIND DRIVEN
WAVES...REACHING 3-5 FT...HIGHEST ON THE OUTER GA WATERS AND OVER
AMZ350. MARINERS ARE ALERTED TO THE POTENTIAL FOR STRONG OR SEVERE
STORMS MOVING OFF THE COAST LATE IN THE DAY.
TONIGHT...WINDS WILL PICK UP SLIGHTLY AS A COLD FRONT APPROACHES
FROM THE WEST. WINDS LOOK TO PEAK 15-20 KT OVER THE GEORGIA
OFFSHORE WATERS AND THE CHARLESTON COUNTY COASTAL WATERS WITH 15
KT ELSEWHERE OUTSIDE OF THE CHARLESTON HARBOR. SEAS WILL REMAIN
2-4 FT NEARSHORE AND 4-5 FT GEORGIA OFFSHORE WATERS...BUT MAY
FLIRT WITH 6 FT AT TIMES ABOUT 15 NM EAST OF THE CHARLESTON COUNTY
COAST. SITUATION LOOKS TO MARGINAL FOR A SECOND PERIOD SMALL CRAFT
ADVISORY...SO WILL DEFER ANY ADVISORY DECISION TO THE NEXT
FORECAST SHIFT.
WEDNESDAY THROUGH SATURDAY...A COLD FRONT WILL SLIP INTO THE
COASTAL WATERS WEDNESDAY AND LIKELY STALL NEAR THE GEORGIA MARINE
ZONES THURSDAY. SOUTHERLY WINDS EARLY WEDNESDAY WILL THUS BECOME
EAST/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY BEHIND THE DESCENDING
FRONT. A BRIEF SURGE IN NORTHEAST FLOW IS POSSIBLE THURSDAY
AFTERNOON...AS HIGH PRESSURE RAPIDLY BUILDS FROM THE NORTH AND
BRIEFLY TIGHTENS THE GRADIENT. WIND SPEEDS COULD INCREASE TO 15 TO
20 KT OVER PORTIONS OF THE WATERS AT THAT TIME...YET CONDITIONS
WILL REMAIN BELOW SMALL CRAFT ADVISORY CONDITIONS. MODERATE
EAST/NORTHEAST FLOW WILL CONTINUE INTO FRIDAY WITHIN A COASTAL
TROUGH TYPE PATTERN...BEFORE WINDS BECOME LIGHTER ON SATURDAY AS
THE CENTER OF HIGH PRESSURE SHIFTS OFFSHORE.
RIP CURRENTS...WE HAVE BUMPED THE RISK UP TO MODERATE TODAY. WITH
SLIGHTLY STRONGER WINDS THAN IN THE PREVIOUS FORECAST...COMBINED
WITH A 2 FOOT SWELL EVERY 10 SECONDS THE RISK APPEARS TO BE
ENHANCED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...ST/WMS
LONG TERM...WMS
AVIATION...
MARINE...
000
FXUS62 KCAE 181420
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1020 AM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...WEAK FRONTAL BOUNDARY REMAINS NORTHWEST OF THE FORECAST
AREA WITH WSR-88D RETURNS SHOWING SCATTERED SHOWERS OVER THE
CENTRAL MIDLANDS THROUGH THE CSRA. WITH SOME CLEARING ALLOWING
TEMPERATURES TO RISE INTO THE LOWER 80S EXPECT SHOWERS TO INCREASE
IN COVERAGE OVER THE NEXT COUPLE OF HOURS. MAIN CONCERN REMAINS
POTENTIAL FOR HEAVY RAIN THIS AFTERNOON AS PWAT VALUES WILL AGAIN
BE AROUND 2 INCHES. HAVE INCREASED POPS TO ACCOUNT FOR CURRENT
RADAR RETURNS AND ADJUSTED TEMPERATURES UP A DEGREE OR TWO.
PREVIOUS DISCUSSION...HIGH MOISTURE WILL CONTINUE TODAY AHEAD OF
THE SLOW MOVING FRONT. CONVERGENCE ASSOCIATED WITH THE
FRONT...HEATING...PLUS ANOTHER IN A SERIES OF MID-LEVEL SHORTWAVE
TROUGHS WILL SUPPORT NUMEROUS SHOWERS AND THUNDERSTORMS.
RADAR TRENDS INDICATE THE BATCH OF THUNDERSTORMS IN WESTERN GEORGIA
EARLY THIS MORNING WILL REACH THE WEST PART OF THE FORECAST AREA
AROUND 14Z. THE SPC WRF DISPLAYS THESE THUNDERSTORMS MOVING
THROUGH MOST OF THE FORECAST AREA DURING THE 16Z TO 20Z TIME
FRAME.
PRECIPITABLE WATER AROUND 2 INCHES AND POSSIBLE TRAINING SUPPORTS
VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS. LOCALIZED FLOODING
WILL BE POSSIBLE. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
DISPLAYS SURFACE-BASED LI/S -3 TO -4 TODAY AND THIS WEAK
INSTABILITY APPEARS REASONABLE BECAUSE OF THE CLOUDINESS AND
NUMEROUS SHOWERS. HOWEVER...THE MODELS AND ESPECIALLY THE GFS
SHOW SIGNIFICANT SHEAR. THE NAM DISPLAYS H85 WIND INCREASING TO
25 TO 30 KNOTS...THE ECMWF 30 TO 35 KNOTS...AND THE GFS 35 TO 40
KNOTS. HEAVY PRECIPITATION LOADING AND THE SHEAR SUPPORTS
ORGANIZED THUNDERSTORMS WITH DAMAGING WIND POSSIBLE.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BECAUSE OF
CLOUDINESS TODAY. USED AN AVERAGE OF THE NAM AND GFS FOR THE WIND
FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT SUPPORTS NUMEROUS
SHOWERS AND THUNDERSTORMS TONIGHT. LEANED TOWARD THE HIGHER POP
GUIDANCE. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING WILL
SUPPORT VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS.
SIGNIFICANT SHEAR MAY ALSO SUPPORT ORGANIZED THUNDERSTORMS WITH
DAMAGING WIND POSSIBLE. THE THREAT OF SEVERE THUNDERSTORMS SHOULD
DIMINISH LATE BECAUSE OF DIMINISHED INSTABILITY ASSOCIATED WITH
PREVIOUS CONVECTION AND NOCTURNAL COOLING. THE NAM AND GFS KEEP
THE FRONT NEAR THE FORECAST AREA WEDNESDAY AND WEDNESDAY NIGHT BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA. THE GFS MOS
INDICATED LOWER POPS COMPARED TO THE NAM AND MAY BE CORRECT
BECAUSE OF THE DIMINISHED MOISTURE AND WIDESPREAD CONVECTION THAT
SHOULD HAVE OCCURRED EARLIER. HOWEVER...BASED ON THE FRONT
LINGERING IN THE AREA AND ANOTHER MID-LEVEL SHORTWAVE TROUGH WE
MAINTAINED CHANCE POPS. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE GFS AND ECMWF GENERALLY SHOWED AN ONSHORE FLOW INTO THE
FORECAST AREA ASSOCIATED WITH HIGH PRESSURE CENTERED OFF THE
MIDDLE ATLANTIC COAST. THERE MAY BE A WEAKNESS IN THE UPPER
RIDGING DURING MUCH OF THE PERIOD. EXPECT SCATTERED MAINLY DIURNAL
THUNDERSTORMS WITH TEMPERATURES NEAR CLIMATOLOGY. THE GFS AND
ECMWF MOS PLUS GFS ENSEMBLE MEANS SUPPORT CHANCE POPS AND NORMAL
TEMPERATURES.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
MIX OF VFR AND MVFR EXPECTED THROUGH THE PERIOD.
WEAK LOW PRESSURE AND FRONTAL BOUNDARY WILL CONTINUE TO PROGRESS
EASTWARD AND WILL IMPACT THE TAF SITES WITH SHOWERS AND
THUNDERSTORMS LATE THIS MORNING INTO THE OVERNIGHT HOURS.
SATELLITE IMAGERY SHOWS SOME DEVELOPING CUMULUS ACROSS THE
SOUTHERN MIDLANDS AND CSRA WITH RADAR RETURNS SHOWING SCATTERED
SHOWERS ALONG AND SOUTH OF CAE/CUB. EXPECT SHOWERS AND
THUNDERSTORMS TO INCREASE IN COVERAGE AND IMPACT THE TAF
SITES...HAVE REMAINED WITH VCTS FOR THE AFTERNOON HOURS AND WILL
UPDATE AS CONFIDENCE IN TIMING INCREASES. CONVECTIVE ACTIVITY WILL
DIMINISH WITH SUNSET...HOWEVER WITH THE FRONT ACROSS THE REGION
SOME SHOWERS WILL LINGER INTO THE OVERNIGHT. POTENTIAL FOR STRATUS
AND FOG AFTER 19/06Z...HOWEVER MUCH WILL DEPEND ON TIMING OF THE
FRONT SO WILL LEAVE OUT OF TAFS ATTM.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 05Z-11Z. NO TAF AMENDMENTS ARE SCHEDULED FOR AGS DURING
THAT TIME. AVIATION INTERESTS ARE ADVISED THAT AGS TENDS TO BE A FOG
PRONE LOCATION...ALSO OFTEN EXPERIENCING VARIABLE CONDITIONS.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS...AS WELL AS LATE NIGHT/EARLY MORNING FOG AND STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 181136
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
736 AM EDT TUE JUN 18 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE AREA TODAY THROUGH
TONIGHT. ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE REGION ON
WEDNESDAY...BUT WITH SOME DRYING OF THE ATMOSPHERE. HIGH PRESSURE
WILL BUILD OVER THE REGION THURSDAY THROUGH THE WEEKEND...BUT WITH
LOW LEVEL MOISTURE PERSISTING.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM EDT TUESDAY...UPPER LEVEL CYCLONIC FLOW CONTINUES TO
PROMOTE A RATHER DESTABILIZED WEATHER PATTERN ACROSS NORTHEAST
GEORGIA AND THE CAROLINAS IN THE NEAR TERM. MEANWHILE...INCREASINGLY
AMPLIFIED SHORTWAVE TROF CONTINUES ITS EASTWARD MOVEMENT ACROSS THE
MIDSOUTH REGION. IN RESPONSE...FALLING HEIGHTS AND AMPLE SURFACE
MOISTURE HAVE ALLOWED FOR CONVECTION TO REMAIN ONGOING ACROSS
PORTIONS OF MIDDLE TENNESSEE AND NORTH CENTRAL ALABAMA. EXPECTING
THIS CONVECTION TO CONTINUE ACROSS NORTHERN GEORGIA AND EAST
TENNESSEE EVENTUALLY MAKING IT ACROSS THE MOUNTAINS INTO THE CWFA.
INTO THE LATE MORNING HOURS AS THE UPPER IMPULSE SWINGS THROUGH.
KEPT CATEGORICAL POPS ACROSS THE MAJORITY OF THE FORECAST AREA
BEGINNING MID MORNING THROUGH TUESDAY AFTERNOON. BEYOND
THAT...TAPERED TO LIKELY POPS ACROSS PORTIONS OF THE UPSTATE AND THE
NORTH CAROLINA PIEDMONT. KEPT CATEGORICAL POPS ACROSS THE HIGHER
TERRAIN AS COLD FRONT WILL BE PUSHING IN AT THAT TIME. CONVERGENCE
ALONG THE FRONT AND SOME MILD INSTABILITY WILL AT LEAST PROVIDE SOME
CHANCE FOR SOME THUNDERSTORM ORGANIZATION. SHEAR PROFILES WILL
INCREASE ALONG THE FRONT THUS LEADING TO THE STRONGEST STORMS OF THE
DAY BEING IN THAT VICINITY. A COMBINATION OF SHOWER AND
THUNDERSTORM ACTIVITY FROM BOTH THE EARLIER PASSING SHORTWAVE AND
THE ENCROACHING COLD FRONT...WILL LEAD TO POTENTIAL FLASH FLOODING.
FORECAST SOUNDINGS INDICATE PWAT VALUE IN EXCESS OF 1.5 INCHES IN
SOME PLACES. THUS...ANY TRAINING THAT DEVELOPS COULD PROVIDE ENOUGH
RAINFALL IN A SHORT PERIOD OF TIME TO INITIATE FLASH FLOODING.
HOWEVER...THINK THAT IF THIS OCCURS IT WILL BE ON A MORE LOCAL SCALE
AND NOT WIDESPREAD THEREFORE OPTED AGAINST ISSUANCE OF FLASH FLOOD
WATCH. CONDITIONS SHOULD IMPROVE SOMEWHAT BEHIND THE FRONT ON
TUESDAY EVENING AS DRIER AIR SPILLS INTO THE REGION. TEMPERATURES
DURING THE NEAR TERM PERIOD WILL BE A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE TO NEAR NORMAL FOR LOWS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM EDT TUESDAY...A POSITIVE TILT CLIPPER TYPE WAVE WILL
CROSS THE FORECAST AREA WED MORNING ALONG WITH THE ENTRANCE REGION
OF A WEAK UPPER JETLET. HOWEVER...A MID LEVEL DRY PUNCH WRAPPING IN
UNDER THE PASSING WAVE WILL CONSPIRE TO LIMIT SHOWER AND TSTM
COVERAGE TO SCATTERED AT BEST...MAINLY IN THE SLIGHTLY MORE UNSTABLE
EASTERN SECTIONS. THE FORECAST MODELS THEN SHOW REDEVELOPMENT BACK
OVER THE MTNS DURING THE AFTERNOON HOURS AS BOUNDARY LAYER
CONVERGENCE INCREASES AHEAD OF A WEAK COLD FRONT SETTLING SOUTHWARD
ALONG THE APPALACHIANS. WILL EXTEND SCATTERED TSTM COVERAGE SE INTO
THE PIEDMONT THROUGH EARLY WED EVENING BEFORE THE ACTIVITY
DISSIPATES.
UPPER HEIGHTS WILL THEN INCREASE IN EARNEST WED NIGHT THROUGH THU
NIGHT. ALTHOUGH MID AND UPPER LEVELS DRY OUT DURING THIS
PERIOD...THE SFC TO 850 MB LAYER WILL REMAIN MOIST AND A SE UPSLOPE
FLOW WILL DEVELOP TO KEEP SOME CLOUDS IN THE PICTURE. WILL FEATURE
MORE OF A DIURNAL SCT MTN TO ISOLD PIEDMONT TSTM PATTERN FOR THU
AFTN AND EVENING...WITH MAX TEMPS REMAINING BELOW CLIMATOLOGY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM EDT TUESDAY...A DOMINANT RIDGE WILL GRADUALLY SET UP
OVER THE SOUTHEAST THROUGH THE MEDIUM RANGE PERIOD. BOUNDARY LAYER
MOISTURE WILL PERSIST FRI THROUGH MON AS BERMUDA HIGH PRESSURE
PUSHES ATLANTIC AND GULF MOISTURE INTO THE REGION ON PERSISTENT SE
TO SW LOW LEVEL FLOW. A PATTERN OF MAINLY DIURNAL CONVECTION WILL BE
ADVERTISED...WITH THE BEST CHANCE POPS OVER THE MOUNTAINS EACH
AFTERNOON AND EVENING. EXPECT A WARMING TREND UNDER THE HIGH
PRESSURE...WITH MAX TEMPS RECOVERING TO AROUND OR SLIGHTLY ABOVE
NORMAL SUNDAY AND MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AT KCLT...SOLID IFR CIGS HAVE PREVAILED AT CHARLOTTE THROUGH THE
EVENING...HOWEVER STILL EXPECTING AN IMPROVEMENT TO MVFR LEVELS A
FEW HOURS AFTER SUNRISE. SCATTERED CONVECTION CONTINUES ACROSS
PORTIONS OF EAST TENNESSEE AND NORTHEAST GEORGIA ASSOCIATED WITH AN
ADVANCING SHORT WAVE TROF. AS UPPER LEVEL SHORT WAVE TROF
APPROACHES...AMPLE MOISTURE IN THE BOUNDARY LAYER WILL PROMPT A
REORGANIZATION OF OVC MVFR CIGS AND SCATTERED SHOWER DEVELOPMENT.
PRECIPITATION COVERAGE WILL CONTINUE TO INCREASE THROUGH THE LATE
MORNING HOURS ACROSS THE REGION THUS ADDED -SHRA BY AROUND 15Z.
CIGS WILL INCREASE TO VFR LEVELS LATE TOMORROW MORNING AS THE
ATMOSPHERE HEATS. FURTHERMORE...INCREASING INSTABILITY THROUGH THE
COLUMN...AND CONVERGENCE ALONG A PASSING FRONTAL BOUNDARY WILL ALLOW
FOR SOME THUNDERSTORM DEVELOPMENT TOMORROW AFTERNOON. WITH
THAT...INCLUDED A TEMPO FROM 20-24Z FOR MVFR VISB WITH TSRA. THE
FRONT WILL LIKELY NOT REACH KCLT UNTIL AROUND THE 02Z TIMEFRAME
SHIFTING WINDS TO A NORTHERLY COMPONENT. WINDS ALONG AND JUST AHEAD
OF THE FRONT COULD BE GUSTY WITH READINGS IN THE 20KT RANGE NOT
BEING OUT OF THE QUESTION.
ELSEWHERE...CIGS WILL RAISE SLIGHTLY ON TUESDAY MORNING BUT SHOULD
REMAIN AT MVFR LEVELS. CIGS WILL FINALLY REBOUND TO VFR CONDITIONS
LATE MORNING AS THE BOUNDARY LAYER WARMS. BY MID TO LATE
MORNING...UPPER LEVEL SHORTWAVE WILL MOVE IN...AND INSTABILITY WILL
HAVE INCREASED SOMEWHAT ALLOWING FOR SOME THUNDERSTORM ACTIVITY TO
DEVELOP. THE WINDOW FOR THUNDERSTORMS LOOKS TO BE A LITTLE NARROWER
FOR THE SOUTH CAROLINA SITES..THUS HANDLED THEM WITH TEMPO GROUPS.
FOR KAVL AND KHKY...DECIDED TO PREVAIL TSRA AS MODEL GUIDANCE
INDICATES INSTABILITY SHOULD REMAIN HIGHER LATER INTO THE DAY AS THE
FRONT APPROACHES. NEAR THE END OF THE PERIOD...THE FRONT WILL MOVE
THROUGH WESTERN NORTH CAROLINA BY AROUND 01Z...AND CONTINUE PUSHING
TO THE SOUTHEAST REACHING THE SOUTH CAROLINA SITES BY AROUND 03-04Z
WEDNESDAY. WINDS ALONG AND JUST AHEAD OF THE FRONT COULD BE GUSTY
WITH READINGS IN THE 20KT RANGE NOT BEING OUT OF THE QUESTION.
OUTLOOK...CONDITIONS WILL IMPROVE SOMEWHAT TUE NIGHT AS DRIER AIR
FILLS IN BEHIND A COLD FRONT. A MODERATELY UNSTABLE ATMOSPHERE
COMBINED WITH EASTERLY FLOW MAY LEAD TO SHOWER AND THUNDERSTORM
DEVELOPMENT MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 89% HIGH 98% HIGH 93% HIGH 90%
KGSP HIGH 91% HIGH 98% HIGH 95% HIGH 98%
KAVL HIGH 95% HIGH 92% HIGH 92% HIGH 91%
KHKY MED 79% HIGH 97% HIGH 92% HIGH 98%
KGMU HIGH 90% HIGH 98% HIGH 93% HIGH 94%
KAND HIGH 83% HIGH 90% HIGH 96% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG
SHORT TERM...HG
LONG TERM...HG
AVIATION...CDG
000
FXUS62 KCHS 181123
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
723 AM EDT TUE JUN 18 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY...THEN SLOWLY
PROGRESS THROUGH THE AREA WEDNESDAY AND THURSDAY. HIGH PRESSURE
WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND AND SETTLE OVER
THE ATLANTIC EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
IT LOOKS TO BE ANOTHER ACTIVE DAY FOR SHOWERS/TSTMS. MODELS ARE
SIMILAR IN SHOWING ANOTHER POTENT SHORTWAVE TRAVERSING SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA THIS AFTERNOON AS INSOLATION
PEAKS. SOME FILTERED SUNSHINE THIS MORNING WILL ALLOW
TEMPERATURES TO RISE QUICKLY...REACHING THE UPPER 80S TO LOWER 90S
AWAY FROM THE BEACHES BY EARLY AFTERNOON. THE RESULTANT SEA BREEZE
AS WELL AS LINGERING CONVECTIVE OUTFLOWS AND POSSIBLY SOME
DIFFERENTIAL HEATING BOUNDARIES WILL SERVE AS THE PRIMARY FOCI FOR
CONVECTIVE DEVELOPMENT. GENERALLY FOLLOWED THE 4KM WRF/S
CONVECTIVE SOLUTION TO CONSTRUCT HOURLY POPS WHICH MATCHES FAIRLY
WELL WITH THE LATEST H3R. GIVEN THAT...WILL GO WITH A 30-70 POP
REGIME TODAY...WITH THE HIGHEST GRIDDED POPS ALIGNED NORTH OF A
METTER-BEAUFORT-CHARLESTON LINE. LOCALLY HEAVY RAINFALL IS
POSSIBLE WITH PWATS 1.8 TO 2.0 INCHES AND AN ISOLATED SEVERE TSTM
OR TWO CAN NOT BE COMPLETELY RULED OUT...ESPECIALLY WHERE UPDRAFTS
ARE ENHANCED DUE TO MESOSCALE BOUNDARY INTERACTIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...SHOWER/TSTM ACTIVITY WILL LINGER INTO THE NIGHT AS A
COLD FRONT MEANDERS CLOSER TO THE REGION. THE FRONT LOOKS TO
REMAIN TO THE WEST PRIOR TO SUNRISE...KEEPING THE AREA WELL WITHIN
THE WARM SECTOR. WEAK IMPULSES/VORTICITY LOBES WILL LIKELY KEEP
AT LEAST SCATTERED ACTIVITY GOING FOR MUCH OF THE NIGHT...ALTHOUGH
IDENTIFYING THE AREAS WHERE POCKETS OF CONVECTION WILL OCCUR IS
PROVING DIFFICULT. WILL KEEP CHANCE POPS GOING ALL NIGHT. LOWS
WILL RANGE FROM THE LOWER 70S INLAND TO THE MID 70S AT THE COAST.
WEDNESDAY...THE WAVE OF LOW PRESSURE RIDING ALONG THE COLD FRONT
WILL HAVE SHIFTED OFF THE MID ATLANTIC COASTLINE BY
DAYBREAK...WHILE THE MAIN SHORTWAVE RAPIDLY PROGRESSES TOWARD THE
EAST COAST AND PUSHES THE FRONT INTO THE FORECAST AREA. THE
COMBINATION OF UPPER LEVEL FORCING WITH FRONTAL CONVERGENCE WILL
SUPPORT SOLID THUNDERSTORM CHANCES UP TO 50 PERCENT DURING THE
DAYTIME HOURS...BEFORE THE FRONT SLIPS FARTHER SOUTH/SOUTHEAST AND
PULLS DEEPEST MOISTURE TOWARD THE ALTAMAHA RIVER AFTER SUNSET.
HIGHER RAIN CHANCES WERE CONSIDERED...YET FAIRLY SIGNIFICANT
TIMING DISCREPANCIES REGARDING THE PROGRESSION OF THE FRONT IS
EVIDENT BETWEEN MODELS...LENDING SOME UNCERTAINTY TO COVERAGE
DETAILS. WILL TREND CONVECTIVE POTENTIAL DOWNWARD FROM NORTH TO
SOUTH OVERNIGHT...WHILE STILL MAINTAINING 20 TO 30 PERCENT POPS
THROUGH THE PRE DAWN HOURS ON THURSDAY. INSTABILITY WILL BE
COMPROMISED BY PERSISTENT CLOUD COVER...AND WITH UNIMPRESSIVE WIND
PROFILES...THE MAIN HAZARD FROM THE STRONGEST CONVECTION WILL BE
HEAVY DOWNPOURS DUE TO SLOW STORM MOTION.
THURSDAY AND FRIDAY...THE FRONT IS EXPECTED TO STALL NEAR THE
SOUTHERN BORDER OF THE FORECAST AREA AS IT BECOMES PARALLEL TO THE
FLOW ALOFT LATE IN THE WEEK. SURFACE HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE NORTH...WITH THE PATTERN EVENTUALLY
TRANSITIONING INTO AN INLAND WEDGE/COASTAL TROUGH TYPE SCENARIO.
EXPECT BEST CONVECTIVE COVERAGE TO BE FOUND ALONG AND SOUTH OF THE
STALLED FRONT DURING THE DAYTIME HOURS...WITH SHOWER/THUNDERSTORM
ACTIVITY SHIFTING MORE TOWARD THE COAST AND OFFSHORE EACH NIGHT
WITHIN COASTAL TROUGH CONVERGENCE.
HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
NORTH TO AROUND 90 DEGREES SOUTH...WITH LOCALLY COOLER CONDITIONS
ALONG THE COASTLINE. OVERNIGHT LOWS WILL TREND A FEW DEGREES
COOLER THAN EARLIER IN THE WEEK...RANGING FROM THE UPPER 60S
INLAND TO LOWER 70S COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
VFR FOR MOST OF THIS MORNING WITH PROBABILITIES INCREASING FOR
SHOWERS/TSTMS AFFECTING THE TERMINALS LATER THIS MORNING INTO THE
AFTERNOON HOURS. HIGHEST PROBABILITIES FOR IMPACTS LOOK TO OCCUR
17-20Z AT KCHS AND 16-19Z AT KSAV...BUT TIMING ADJUSTMENTS WILL BE
NEEDED AS THE DAY PROGRESSES. CAPPED CONDITIONS AT MVFR FOR NOW...
BUT BRIEF BOUTS OF IFR OR LOWER VSBYS ARE POSSIBLE IN HEAVY
CONVECTIVE RAINS. THE RISK FOR SHOWER/TSTMS WILL LINGER INTO MOST
OF THE NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. ITS UNCLEAR
WHERE EXACTLY ANY LINES OF CONVECTION WILL OCCUR...SO DID NOT
INCLUDE ANY MENTION OF PCPN DURING THE NIGHT TIME HOURS.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS TUESDAY THROUGH
THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA...MAINLY DURING THE AFTERNOON HOURS.
&&
.MARINE...
TODAY...SOUTHERLY FLOW REGIME WILL REMAIN IN TACT. WINDS WILL
GENERALLY REMAIN 10-15 KT WITH SEAS 2-4 FT NEARSHORE WATERS AND
4-5 FT OFFSHORE WATERS.
TONIGHT...WINDS WILL PICK UP SLIGHTLY AS A COLD FRONT APPROACHES
FROM THE WEST. WINDS LOOK TO PEAK 15-20 KT OVER THE GEORGIA
OFFSHORE WATERS AND THE CHARLESTON COUNTY COASTAL WATERS WITH 15
KT ELSEWHERE OUTSIDE OF THE CHARLESTON HARBOR. SEAS WILL REMAIN
2-4 FT NEARSHORE AND 4-5 FT GEORGIA OFFSHORE WATERS...BUT MAY
FLIRT WITH 6 FT AT TIMES ABOUT 15 NM EAST OF THE CHARLESTON COUNTY
COAST. SITUATION LOOKS TO MARGINAL FOR A SECOND PERIOD SMALL CRAFT
ADVISORY...SO WILL DEFER ANY ADVISORY DECISION TO THE NEXT
FORECAST SHIFT.
WEDNESDAY THROUGH SATURDAY...A COLD FRONT WILL SLIP INTO THE
COASTAL WATERS WEDNESDAY AND LIKELY STALL NEAR THE GEORGIA MARINE
ZONES THURSDAY. SOUTHERLY WINDS EARLY WEDNESDAY WILL THUS BECOME
EAST/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY BEHIND THE DESCENDING
FRONT. A BRIEF SURGE IN NORTHEAST FLOW IS POSSIBLE THURSDAY
AFTERNOON...AS HIGH PRESSURE RAPIDLY BUILDS FROM THE NORTH AND
BRIEFLY TIGHTENS THE GRADIENT. WIND SPEEDS COULD INCREASE TO 15 TO
20 KT OVER PORTIONS OF THE WATERS AT THAT TIME...YET CONDITIONS
WILL REMAIN BELOW SMALL CRAFT ADVISORY CONDITIONS. MODERATE
EAST/NORTHEAST FLOW WILL CONTINUE INTO FRIDAY WITHIN A COASTAL
TROUGH TYPE PATTERN...BEFORE WINDS BECOME LIGHTER ON SATURDAY AS
THE CENTER OF HIGH PRESSURE SHIFTS OFFSHORE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/WMS
000
FXUS62 KCAE 181009
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
609 AM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH MOISTURE WILL CONTINUE TODAY AHEAD OF THE SLOW MOVING FRONT.
CONVERGENCE ASSOCIATED WITH THE FRONT...HEATING...PLUS ANOTHER IN
A SERIES OF MID-LEVEL SHORTWAVE TROUGHS WILL SUPPORT NUMEROUS
SHOWERS AND THUNDERSTORMS.
RADAR TRENDS INDICATE THE BATCH OF THUNDERSTORMS IN WESTERN GEORGIA
EARLY THIS MORNING WILL REACH THE WEST PART OF THE FORECAST AREA
AROUND 14Z. THE SPC WRF DISPLAYS THESE THUNDERSTORMS MOVING
THROUGH MOST OF THE FORECAST AREA DURING THE 16Z TO 20Z TIME
FRAME.
PRECIPITABLE WATER AROUND 2 INCHES AND POSSIBLE TRAINING SUPPORTS
VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS. LOCALIZED FLOODING
WILL BE POSSIBLE. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
DISPLAYS SURFACE-BASED LI/S -3 TO -4 TODAY AND THIS WEAK
INSTABILITY APPEARS REASONABLE BECAUSE OF THE CLOUDINESS AND
NUMEROUS SHOWERS. HOWEVER...THE MODELS AND ESPECIALLY THE GFS
SHOW SIGNIFICANT SHEAR. THE NAM DISPLAYS H85 WIND INCREASING TO
25 TO 30 KNOTS...THE ECMWF 30 TO 35 KNOTS...AND THE GFS 35 TO 40
KNOTS. HEAVY PRECIPITATION LOADING AND THE SHEAR SUPPORTS
ORGANIZED THUNDERSTORMS WITH DAMAGING WIND POSSIBLE.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BECAUSE OF
CLOUDINESS TODAY. USED AN AVERAGE OF THE NAM AND GFS FOR THE WIND
FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT SUPPORTS NUMEROUS
SHOWERS AND THUNDERSTORMS TONIGHT. LEANED TOWARD THE HIGHER POP
GUIDANCE. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING WILL
SUPPORT VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS.
SIGNIFICANT SHEAR MAY ALSO SUPPORT ORGANIZED THUNDERSTORMS WITH
DAMAGING WIND POSSIBLE. THE THREAT OF SEVERE THUNDERSTORMS SHOULD
DIMINISH LATE BECAUSE OF DIMINISHED INSTABILITY ASSOCIATED WITH
PREVIOUS CONVECTION AND NOCTURNAL COOLING. THE NAM AND GFS KEEP
THE FRONT NEAR THE FORECAST AREA WEDNESDAY AND WEDNESDAY NIGHT BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA. THE GFS MOS
INDICATED LOWER POPS COMPARED TO THE NAM AND MAY BE CORRECT
BECAUSE OF THE DIMINISHED MOISTURE AND WIDESPREAD CONVECTION THAT
SHOULD HAVE OCCURRED EARLIER. HOWEVER...BASED ON THE FRONT
LINGERING IN THE AREA AND ANOTHER MID-LEVEL SHORTWAVE TROUGH WE
MAINTAINED CHANCE POPS. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE GFS AND ECMWF GENERALLY SHOWED AN ONSHORE FLOW INTO THE
FORECAST AREA ASSOCIATED WITH HIGH PRESSURE CENTERED OFF THE
MIDDLE ATLANTIC COAST. THERE MAY BE A WEAKNESS IN THE UPPER
RIDGING DURING MUCH OF THE PERIOD. EXPECT SCATTERED MAINLY DIURNAL
THUNDERSTORMS WITH TEMPERATURES NEAR CLIMATOLOGY. THE GFS AND
ECMWF MOS PLUS GFS ENSEMBLE MEANS SUPPORT CHANCE POPS AND NORMAL
TEMPERATURES.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
MAINLY MVFR/IFR CIGS ACROSS THE AREA THIS MORNING. EXPECT
IMPROVEMENT TO VFR AT ALL TAF SITES BY AROUND 14Z. AFTER ANY MORNING
RESTRICTIONS...EXPECT VFR TODAY OUTSIDE OF SCATTERED TO POSSIBLY
NUMEROUS MAINLY AFTERNOON/EVENING THUNDERSTORMS.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 05Z-11Z. NO TAF AMENDMENTS ARE SCHEDULED FOR AGS DURING
THAT TIME. AVIATION INTERESTS ARE ADVISED THAT AGS TENDS TO BE A FOG
PRONE LOCATION...ALSO OFTEN EXPERIENCING VARIABLE CONDITIONS.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 180823
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
423 AM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH MOISTURE WILL CONTINUE TODAY AHEAD OF THE SLOW MOVING FRONT.
CONVERGENCE ASSOCIATED WITH THE FRONT...HEATING...PLUS ANOTHER IN
A SERIES OF MID-LEVEL SHORTWAVE TROUGHS WILL SUPPORT NUMEROUS
SHOWERS AND THUNDERSTORMS.
RADAR TRENDS INDICATE THE BATCH OF THUNDERSTORMS NEAR THE ALABAMA
AND GEORGIA BORDER EARLY THIS MORNING WILL REACH THE WEST PART OF
THE FORECAST AREA AROUND 14Z. THE SPC WRF DISPLAYS THESE
THUNDERSTORMS MOVING THROUGH THE FORECAST AREA DURING THE 16Z TO
20Z TIME FRAME.
PRECIPITABLE WATER AROUND 2 INCHES AND POSSIBLE TRAINING SUPPORTS
VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS. LOCALIZED FLOODING
WILL BE POSSIBLE. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
DISPLAYS SURFACE-BASED LI/S -3 TO -4 TODAY AND THIS WEAK
INSTABILITY APPEARS REASONABLE BECAUSE OF THE CLOUDINESS AND
NUMEROUS SHOWERS. HOWEVER...THE MODELS AND ESPECIALLY THE GFS
SHOW SIGNIFICANT SHEAR. THE NAM DISPLAYS H85 WIND INCREASING TO
25 TO 30 KNOTS...THE ECMWF 30 TO 35 KNOTS...AND THE GFS 35 TO 40
KNOTS. HEAVY PRECIPITATION LOADING AND THE SHEAR SUPPORTS
ORGANIZED THUNDERSTORMS WITH DAMAGING WIND POSSIBLE.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BECAUSE OF
CLOUDINESS TODAY. USED AN AVERAGE OF THE NAM AND GFS FOR THE WIND
FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT SUPPORTS NUMEROUS
SHOWERS AND THUNDERSTORMS TONIGHT. LEANED TOWARD THE HIGHER POP
GUIDANCE. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING WILL
SUPPORT VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS.
SIGNIFICANT SHEAR MAY ALSO SUPPORT ORGANIZED THUNDERSTORMS WITH
DAMAGING WIND POSSIBLE. THE THREAT OF SEVERE THUNDERSTORMS SHOULD
DIMINISH LATE BECAUSE OF DIMINISHED INSTABILITY ASSOCIATED WITH
PREVIOUS CONVECTION AND NOCTURNAL COOLING. THE NAM AND GFS KEEP
THE FRONT NEAR THE FORECAST AREA WEDNESDAY AND WEDNESDAY NIGHT BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA. THE GFS MOS
INDICATED LOWER POPS COMPARED TO THE NAM AND MAY BE CORRECT
BECAUSE OF THE DIMINISHED MOISTURE AND WIDESPREAD CONVECTION THAT
SHOULD HAVE OCCURRED EARLIER. HOWEVER...BASED ON THE FRONT
LINGERING IN THE AREA AND ANOTHER MID-LEVEL SHORTWAVE TROUGH WE
MAINTAINED CHANCE POPS. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE GFS AND ECMWF GENERALLY SHOWED AN ONSHORE FLOW INTO THE
FORECAST AREA ASSOCIATED WITH HIGH PRESSURE CENTERED OFF THE
MIDDLE ATLANTIC COAST. THERE MAY BE A WEAKNESS IN THE UPPER
RIDGING DURING MUCH OF THE PERIOD. EXPECT SCATTERED MAINLY DIURNAL
THUNDERSTORMS WITH TEMPERATURES NEAR CLIMATOLOGY. THE GFS AND
ECMWF MOS PLUS GFS ENSEMBLE MEANS SUPPORT CHANCE POPS AND NORMAL
TEMPERATURES.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
MOST OF THE CONVECTIVE ACTIVITY HAS MOVED EAST OF THE FORECAST AREA
EARLY THIS MORNING. CONCERN WILL NOW SHIFT TO ANY FOG/STRATUS
POTENTIAL. RAINFALL HAS OCCURRED AT ALL THE TERMINALS AND CURRENT
DEWPOINT DEPRESSIONS LOW. HOWEVER...LATEST CAE VAD WIND PROFILE
INDICATING A SW 20 TO 25 KT LOW LEVEL JET...AND SATELLITE SUGGESTS
CONSIDERABLE UPPER LEVEL CONVECTIVE DEBRIS CLOUD COVER COULD
LINGER...WHICH WOULD WORK AGAINST FOG FORMATION. LATEST HIGH RES
MODEL GUIDANCE SUGGESTING LOWER CLOUDS POSSIBLE WITH MVFR TO IFR
CIGS. FOR NOW...WILL INDICATE PERIOD OF IFR OR BRIEF LIFR CONDITIONS
DURING THE PRE-DAWN HOURS.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED TO POSSIBLY NUMEROUS MAINLY AFTERNOON/EVENING
THUNDERSTORMS.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 05Z-11Z. NO TAF AMENDMENTS ARE SCHEDULED FOR AGS DURING
THAT TIME. AVIATION INTERESTS ARE ADVISED THAT AGS TENDS TO BE A FOG
PRONE LOCATION...ALSO OFTEN EXPERIENCING VARIABLE CONDITIONS.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 180754
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
354 AM EDT TUE JUN 18 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH SUNRISE...A STRONG CLUSTER OF TSTMS WHICH MOVED THROUGH
THE CHARLESTON METRO AREA AROUND 3 AM IS PUSHING STEADILY
OFFSHORE. ONCE THIS ACTIVITY MOVES INTO THE ATLANTIC...EXPECT
RELATIVELY QUIET CONDITIONS THROUGH SUNRISE. SATELLITE SHOWS SOME
CLEARING OCCURRING ACROSS SOUTHEAST GEORGIA WHICH COULD WORK
FARTHER UP ALONG THE LOWER SOUTH CAROLINA COAST OVER THE NEXT FEW
HOURS. CLOUD SEE SOME PATCHES OF LOW CLOUDS AND FOG FORM GIVEN THE
LIGHT WIND FIELDS THAT ARE IN PLACE.
TODAY...IT LOOKS TO BE ANOTHER ACTIVE DAY FOR SHOWERS/TSTMS. MODELS
ARE SIMILAR IN SHOWING ANOTHER POTENT SHORTWAVE TRAVERSING
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THIS AFTERNOON AS
INSOLATION PEAKS. SOME FILTERED SUNSHINE THIS MORNING SHOULD ALLOW
TEMPERATURES TO RISE QUICKLY...REACHING THE UPPER 80S TO LOWER 90S
AWAY FROM THE BEACHES BY EARLY AFTERNOON. THE RESULTANT SEA
BREEZE AS WELL AS LINGERING CONVECTIVE OUTFLOWS AND POSSIBLY SOME
DIFFERENTIAL HEATING BOUNDARIES WILL SERVE AS THE PRIMARY FOCI FOR
CONVECTIVE DEVELOPMENT. GENERALLY FOLLOWED THE 4KM WRF/S
CONVECTIVE SOLUTION TO CONSTRUCT HOURLY POPS WHICH MATCHES FAIRLY
WELL WITH THE LATEST H3R. GIVEN THAT...WILL GO WITH A 50-70 POP
REGIME TODAY...WITH THE HIGHEST GRIDDED POPS ALIGNED NORTH OF A
METTER-BEAUFORT-CHARLESTON LINE. LOCALLY HEAVY RAINFALL IS
POSSIBLE WITH PWATS 1.8 TO 2.0 INCHES AND AN ISOLATED SEVERE
TSTM OR TWO CAN NOT BE COMPLETELY RULED OUT...ESPECIALLY WHERE
UPDRAFTS ARE ENHANCED DUE TO MESOSCALE BOUNDARY INTERACTIONS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
TONIGHT...SHOWER/TSTM ACTIVITY WILL LINGER INTO THE NIGHT AS A
COLD FRONT MEANDERS CLOSER TO THE REGION. THE FRONT LOOKS TO
REMAIN TO THE WEST PRIOR TO SUNRISE...KEEPING THE AREA WELL WITHIN
THE WARM SECTOR. WEAK IMPULSES/VORTICITY LOBES WILL LIKELY KEEP
AT LEAST SCATTERED ACTIVITY GOING FOR MUCH OF THE NIGHT...ALTHOUGH
IDENTIFYING THE AREAS WHERE POCKETS OF CONVECTION WILL OCCUR IS
PROVING DIFFICULT. WILL KEEP CHANCE POPS GOING ALL NIGHT. LOWS
WILL RANGE FROM THE LOWER 70S INLAND TO THE MID 70S AT THE COAST.
WEDNESDAY...THE WAVE OF LOW PRESSURE RIDING ALONG THE COLD FRONT
WILL HAVE SHIFTED OFF THE MID ATLANTIC COASTLINE BY
DAYBREAK...WHILE THE MAIN SHORTWAVE RAPIDLY PROGRESSES TOWARD THE
EAST COAST AND PUSHES THE FRONT INTO THE FORECAST AREA. THE
COMBINATION OF UPPER LEVEL FORCING WITH FRONTAL CONVERGENCE WILL
SUPPORT SOLID THUNDERSTORM CHANCES UP TO 50 PERCENT DURING THE
DAYTIME HOURS...BEFORE THE FRONT SLIPS FARTHER SOUTH/SOUTHEAST AND
PULLS DEEPEST MOISTURE TOWARD THE ALTAMAHA RIVER AFTER SUNSET.
HIGHER RAIN CHANCES WERE CONSIDERED...YET FAIRLY SIGNIFICANT
TIMING DISCREPANCIES REGARDING THE PROGRESSION OF THE FRONT IS
EVIDENT BETWEEN MODELS...LENDING SOME UNCERTAINTY TO COVERAGE
DETAILS. WILL TREND CONVECTIVE POTENTIAL DOWNWARD FROM NORTH TO
SOUTH OVERNIGHT...WHILE STILL MAINTAINING 20 TO 30 PERCENT POPS
THROUGH THE PRE DAWN HOURS ON THURSDAY. INSTABILITY WILL BE
COMPROMISED BY PERSISTENT CLOUD COVER...AND WITH UNIMPRESSIVE WIND
PROFILES...THE MAIN HAZARD FROM THE STRONGEST CONVECTION WILL BE
HEAVY DOWNPOURS DUE TO SLOW STORM MOTION.
THURSDAY AND FRIDAY...THE FRONT IS EXPECTED TO STALL NEAR THE
SOUTHERN BORDER OF THE FORECAST AREA AS IT BECOMES PARALLEL TO THE
FLOW ALOFT LATE IN THE WEEK. SURFACE HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE NORTH...WITH THE PATTERN EVENTUALLY
TRANSITIONING INTO AN INLAND WEDGE/COASTAL TROUGH TYPE SCENARIO.
EXPECT BEST CONVECTIVE COVERAGE TO BE FOUND ALONG AND SOUTH OF THE
STALLED FRONT DURING THE DAYTIME HOURS...WITH SHOWER/THUNDERSTORM
ACTIVITY SHIFTING MORE TOWARD THE COAST AND OFFSHORE EACH NIGHT
WITHIN COASTAL TROUGH CONVERGENCE.
HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
NORTH TO AROUND 90 DEGREES SOUTH...WITH LOCALLY COOLER CONDITIONS
ALONG THE COASTLINE. OVERNIGHT LOWS WILL TREND A FEW DEGREES
COOLER THAN EARLIER IN THE WEEK...RANGING FROM THE UPPER 60S
INLAND TO LOWER 70S COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A WEAK INLAND WEDGE/COASTAL TROUGH PATTERN WILL PERSIST INTO
SATURDAY...BEFORE THE TROUGH DAMPENS BY SUNDAY AS HIGH PRESSURE
SETTLES OVER THE ATLANTIC. THE FORECAST AREA WILL THEN REMAIN
ALONG THE WESTERN PERIPHERY OF THE ATLANTIC HIGH PRESSURE INTO
EARLY NEXT WEEK. SHOWER/THUNDERSTORM CHANCES WILL RANGE FROM
AROUND 20 TO 30 PERCENT EACH AFTERNOON AND EARLY EVENING...BEFORE
DIMINISHING OVERNIGHT AS MORE TYPICAL FOR EARLY SUMMER. THE
INITIALLY WEAK AND ILL DEFINED UPPER LEVEL PATTERN WILL TRANSITION
INTO BROAD RIDGING ALOFT...SUPPORTING A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SATURDAY AND SUNDAY WILL WARM INTO THE LOWER 90S BY
MONDAY AND TUESDAY.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
TSTMS WILL MOVE ACROSS THE KCHS TERMINAL 06-08Z BRINGING GUSTY
WINDS AND LOCALIZED IFR VSBYS. THE NEAR TERM RISK FOR TSTMS SHOULD
END BY 08Z WITH A RETURN TO VFR CONDITIONS. VFR WILL DOMINATE AT
KSAV THROUGH SUNRISE WITH THE BULK OF THE TSTMS ACTIVITY PASSING
TO THE NORTH OF THAT TERMINAL. HIGH RESOLUTION MODELS SHOW ANOTHER
BATCH OF SHOWERS/TSTMS MOVING ACROSS THE COASTAL CORRIDOR BY LATE
MORNING AFTERNOON AS A POTENT SHORTWAVE PUSHES THROUGH. WILL
CARRY TEMPO GROUPS FOR 4SM TSRA BR BKN040CB FROM 18-21Z AT KCHS
AND 16-19Z AT KSAV TO COVER. ADJUSTMENTS WILL MOST CERTAINLY BE
NEEDED AS THE MORNING PROGRESSES.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS TUESDAY THROUGH
THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA...MAINLY DURING THE AFTERNOON HOURS.
&&
.MARINE...
TODAY...SOUTHERLY FLOW REGIME WILL REMAIN IN TACT. WINDS WILL
GENERALLY REMAIN 10-15 KT WITH SEAS 2-4 FT NEARSHORE WATERS AND
4-5 FT OFFSHORE WATERS.
TONIGHT...WINDS WILL PICK UP SLIGHTLY AS A COLD FRONT APPROACHES
FROM THE WEST. WINDS LOOK TO PEAK 15-20 KT OVER THE GEORGIA
OFFSHORE WATERS AND THE CHARLESTON COUNTY COASTAL WATERS WITH 15
KT ELSEWHERE OUTSIDE OF THE CHARLESTON HARBOR. SEAS WILL REMAIN
2-4 FT NEARSHORE AND 4-5 FT GEORGIA OFFSHORE WATERS...BUT MAY
FLIRT WITH 6 FT AT TIMES ABOUT 15 NM EAST OF THE CHARLESTON COUNTY
COAST. SITUATION LOOKS TO MARGINAL FOR A SECOND PERIOD SMALL CRAFT
ADVISORY...SO WILL DEFER ANY ADVISORY DECISION TO THE NEXT
FORECAST SHIFT.
WEDNESDAY THROUGH SATURDAY...A COLD FRONT WILL SLIP INTO THE
COASTAL WATERS WEDNESDAY AND LIKELY STALL NEAR THE GEORGIA MARINE
ZONES THURSDAY. SOUTHERLY WINDS EARLY WEDNESDAY WILL THUS BECOME
EAST/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY BEHIND THE DESCENDING
FRONT. A BRIEF SURGE IN NORTHEAST FLOW IS POSSIBLE THURSDAY
AFTERNOON...AS HIGH PRESSURE RAPIDLY BUILDS FROM THE NORTH AND
BRIEFLY TIGHTENS THE GRADIENT. WIND SPEEDS COULD INCREASE TO 15 TO
20 KT OVER PORTIONS OF THE WATERS AT THAT TIME...YET CONDITIONS
WILL REMAIN BELOW SMALL CRAFT ADVISORY CONDITIONS. MODERATE
EAST/NORTHEAST FLOW WILL CONTINUE INTO FRIDAY WITHIN A COASTAL
TROUGH TYPE PATTERN...BEFORE WINDS BECOME LIGHTER ON SATURDAY AS
THE CENTER OF HIGH PRESSURE SHIFTS OFFSHORE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/WMS
000
FXUS62 KGSP 180748
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
348 AM EDT TUE JUN 18 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE AREA TODAY THROUGH
TONIGHT. ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE REGION ON
WEDNESDAY...BUT WITH SOME DRYING OF THE ATMOSPHERE. HIGH PRESSURE
WILL BUILD OVER THE REGION THURSDAY THROUGH THE WEEKEND...BUT WITH
LOW LEVEL MOISTURE PERSISTING.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM EDT TUESDAY...UPPER LEVEL CYCLONIC FLOW CONTINUES TO
PROMOTE A RATHER DESTABILIZED WEATHER PATTERN ACROSS NORTHEAST
GEORGIA AND THE CAROLINAS IN THE NEAR TERM. MEANWHILE...INCREASINGLY
AMPLIFIED SHORTWAVE TROF CONTINUES ITS EASTWARD MOVEMENT ACROSS THE
MIDSOUTH REGION. IN RESPONSE...FALLING HEIGHTS AND AMPLE SURFACE
MOISTURE HAVE ALLOWED FOR CONVECTION TO REMAIN ONGOING ACROSS
PORTIONS OF MIDDLE TENNESSEE AND NORTH CENTRAL ALABAMA. EXPECTING
THIS CONVECTION TO CONTINUE ACROSS NORTHERN GEORGIA AND EAST
TENNESSEE EVENTUALLY MAKING IT ACROSS THE MOUNTAINS INTO THE CWFA.
INTO THE LATE MORNING HOURS AS THE UPPER IMPULSE SWINGS THROUGH.
KEPT CATEGORICAL POPS ACROSS THE MAJORITY OF THE FORECAST AREA
BEGINNING MID MORNING THROUGH TUESDAY AFTERNOON. BEYOND
THAT...TAPERED TO LIKELY POPS ACROSS PORTIONS OF THE UPSTATE AND THE
NORTH CAROLINA PIEDMONT. KEPT CATEGORICAL POPS ACROSS THE HIGHER
TERRAIN AS COLD FRONT WILL BE PUSHING IN AT THAT TIME. CONVERGENCE
ALONG THE FRONT AND SOME MILD INSTABILITY WILL AT LEAST PROVIDE SOME
CHANCE FOR SOME THUNDERSTORM ORGANIZATION. SHEAR PROFILES WILL
INCREASE ALONG THE FRONT THUS LEADING TO THE STRONGEST STORMS OF THE
DAY BEING IN THAT VICINITY. A COMBINATION OF SHOWER AND
THUNDERSTORM ACTIVITY FROM BOTH THE EARLIER PASSING SHORTWAVE AND
THE ENCROACHING COLD FRONT...WILL LEAD TO POTENTIAL FLASH FLOODING.
FORECAST SOUNDINGS INDICATE PWAT VALUE IN EXCESS OF 1.5 INCHES IN
SOME PLACES. THUS...ANY TRAINING THAT DEVELOPS COULD PROVIDE ENOUGH
RAINFALL IN A SHORT PERIOD OF TIME TO INITIATE FLASH FLOODING.
HOWEVER...THINK THAT IF THIS OCCURS IT WILL BE ON A MORE LOCAL SCALE
AND NOT WIDESPREAD THEREFORE OPTED AGAINST ISSUANCE OF FLASH FLOOD
WATCH. CONDITIONS SHOULD IMPROVE SOMEWHAT BEHIND THE FRONT ON
TUESDAY EVENING AS DRIER AIR SPILLS INTO THE REGION. TEMPERATURES
DURING THE NEAR TERM PERIOD WILL BE A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE TO NEAR NORMAL FOR LOWS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM EDT TUESDAY...A POSITIVE TILT CLIPPER TYPE WAVE WILL
CROSS THE FORECAST AREA WED MORNING ALONG WITH THE ENTRANCE REGION
OF A WEAK UPPER JETLET. HOWEVER...A MID LEVEL DRY PUNCH WRAPPING IN
UNDER THE PASSING WAVE WILL CONSPIRE TO LIMIT SHOWER AND TSTM
COVERAGE TO SCATTERED AT BEST...MAINLY IN THE SLIGHTLY MORE UNSTABLE
EASTERN SECTIONS. THE FORECAST MODELS THEN SHOW REDEVELOPMENT BACK
OVER THE MTNS DURING THE AFTERNOON HOURS AS BOUNDARY LAYER
CONVERGENCE INCREASES AHEAD OF A WEAK COLD FRONT SETTLING SOUTHWARD
ALONG THE APPALACHIANS. WILL EXTEND SCATTERED TSTM COVERAGE SE INTO
THE PIEDMONT THROUGH EARLY WED EVENING BEFORE THE ACTIVITY
DISSIPATES.
UPPER HEIGHTS WILL THEN INCREASE IN EARNEST WED NIGHT THROUGH THU
NIGHT. ALTHOUGH MID AND UPPER LEVELS DRY OUT DURING THIS
PERIOD...THE SFC TO 850 MB LAYER WILL REMAIN MOIST AND A SE UPSLOPE
FLOW WILL DEVELOP TO KEEP SOME CLOUDS IN THE PICTURE. WILL FEATURE
MORE OF A DIURNAL SCT MTN TO ISOLD PIEDMONT TSTM PATTERN FOR THU
AFTN AND EVENING...WITH MAX TEMPS REMAINING BELOW CLIMATOLOGY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM EDT TUESDAY...A DOMINANT RIDGE WILL GRADUALLY SET UP
OVER THE SOUTHEAST THROUGH THE MEDIUM RANGE PERIOD. BOUNDARY LAYER
MOISTURE WILL PERSIST FRI THROUGH MON AS BERMUDA HIGH PRESSURE
PUSHES ATLANTIC AND GULF MOISTURE INTO THE REGION ON PERSISTENT SE
TO SW LOW LEVEL FLOW. A PATTERN OF MAINLY DIURNAL CONVECTION WILL BE
ADVERTISED...WITH THE BEST CHANCE POPS OVER THE MOUNTAINS EACH
AFTERNOON AND EVENING. EXPECT A WARMING TREND UNDER THE HIGH
PRESSURE...WITH MAX TEMPS RECOVERING TO AROUND OR SLIGHTLY ABOVE
NORMAL SUNDAY AND MONDAY.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
AT KCLT...BORDERLINE VFR/MVFR CONDITIONS WILL PREVAIL THROUGH THE
OVERNIGHT HOURS BEFORE CIGS GRADUALLY LOWER TO SOLID MVFR LEVELS.
AS UPPER LEVEL SHORT WAVE TROF APPROACHES AROUND MID MORNING...AMPLE
MOISTURE IN THE BOUNDARY LAYER WILL PROMPT A REORGANIZATION OF OVC
MVFR CIGS AND SCATTERED SHOWER DEVELOPMENT. PRECIPITATION COVERAGE
WILL CONTINUE TO INCREASE THROUGH THE LATE MORNING HOURS ACROSS THE
REGION THUS STARTED WITH VCSH AND GAVE WAY TO -SHRA BY AROUND 14Z.
CIGS WILL INCREASE TO VFR LEVELS LATE TOMORROW MORNING AS THE
ATMOSPHERE HEATS. FURTHERMORE...INCREASING INSTABILITY THROUGH THE
COLUMN...AND CONVERGENCE ALONG A PASSING FRONTAL BOUNDARY WILL ALLOW
FOR SOME THUNDERSTORM DEVELOPMENT TOMORROW AFTERNOON. WITH
THAT...INCLUDED A PROB30 GROUP FROM 18-24Z FOR MVFR VISB WITH
TSRA. THE FRONT WILL LIKELY NOT REACH KCLT UNTIL AROUND THE 02Z
TIMEFRAME SHIFTING WINDS TO A NORTHERLY COMPONENT. WINDS ALONG AND
JUST AHEAD OF THE FRONT COULD BE GUSTY WITH READINGS IN THE 20KT
RANGE NOT BEING OUT OF THE QUESTION.
ELSEWHERE...PREVAILED LOW END MVFR CIGS THROUGH THE FIRST PERIOD OF
THE TAF CYCLE DUE TO CONVECTIVE CLOUD DEBRIS ACROSS THE REGION.
BEYOND THAT...CIGS WILL RAISE SLIGHTLY ON TUESDAY MORNING BUT
SHOULD REMAIN AT MVFR LEVELS. CIGS WILL FINALLY REBOUND TO VFR
CONDITIONS LATE MORNING AS THE BOUNDARY LAYER WARMS.
FURTHERMORE...KEPT SOME MENTION OF VCSH AT ALL SITES AS SCATTERED
LIGHT SHOWERS CONTINUE ACROSS THE REGION. BY MID TO LATE
MORNING...UPPER LEVEL SHORTWAVE WILL MOVE IN...AND INSTABILITY WILL
HAVE INCREASED SOMEWHAT ALLOWING FOR SOME THUNDERSTORM ACTIVITY TO
DEVELOP. THE WINDOW FOR THUNDERSTORMS LOOKS TO BE A LITTLE NARROWER
FOR THE SOUTH CAROLINA SITES..THUS HANDLED THEM WITH TEMP GROUPS.
FOR KAVL AND KHKY...DECIDE TO GO WITH A PROB30 AS MODEL GUIDANCE
INDICATES INSTABILITY SHOULD REMAIN HIGHER LATER INTO THE DAY AS THE
FRONT APPROACHES. NEAR THE END OF THE PERIOD...THE FRONT WILL MOVE
THROUGH WESTERN NORTH CAROLINA BY AROUND 00Z...AND CONTINUE PUSHING
TO THE SOUTHEAST REACHING THE SOUTH CAROLINA SITES BY AROUND 03-04Z
WEDNESDAY. WINDS ALONG AND JUST AHEAD OF THE FRONT COULD BE GUSTY
WITH READINGS IN THE 20KT RANGE NOT BEING OUT OF THE QUESTION.
OUTLOOK...CONDITIONS WILL IMPROVE SOMEWHAT TUE NIGHT AS DRIER AIR
FILLS IN BEHIND A COLD FRONT. A MODERATELY UNSTABLE ATMOSPHERE
COMBINED WITH EASTERLY FLOW MAY LEAD TO SHOWER AND THUNDERSTORM
DEVELOPMENT MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
07-13Z 13-19Z 19-01Z 01-07Z
KCLT MED 72% HIGH 91% HIGH 100% HIGH 93%
KGSP MED 71% HIGH 92% HIGH 95% HIGH 95%
KAVL HIGH 80% HIGH 88% HIGH 93% HIGH 82%
KHKY MED 70% HIGH 81% HIGH 92% HIGH 92%
KGMU MED 64% HIGH 94% HIGH 95% HIGH 90%
KAND MED 77% HIGH 84% HIGH 99% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG
SHORT TERM...HG
LONG TERM...HG
AVIATION...CDG
000
FXUS62 KCAE 180715
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
315 AM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH MOISTURE WILL CONTINUE TODAY AHEAD OF THE SLOW MOVING FRONT.
CONVERGENCE ASSOCIATED WITH THE FRONT...HEATING...PLUS ANOTHER IN
A SERIES OF MID-LEVEL SHORTWAVE TROUGHS SHOULD SUPPORT NUMEROUS
SHOWERS AND THUNDERSTORMS. THE HIGH RESOLUTION MODELS SUPPORT THE
GREATEST COVERAGE IN THE AFTERNOON. PRECIPITABLE WATER AROUND 2
INCHES AND POSSIBLE TRAINING SUPPORT VERY HEAVY RAIN WITH SOME OF
THE THUNDERSTORMS. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
DISPLAYS SURFACE-BASED LI/S -3 TO -4 TODAY. HOWEVER...BOTH THE NAM
AND ESPECIALLY THE GFS SHOW SIGNIFICANT SHEAR. THE NAM SHOWS H85
WIND INCREASING TO 25 TO 30 KNOTS. THE GFS DISPLAYS 35 TO 40
KNOTS. THE GFS MAY BE OVERDONE...BUT IT HAS SUPPORT FROM THE 12Z
YESTERDAY RUN OF THE ECMWF. HEAVY PRECIPITATION LOADING AND THE
SHEAR SUPPORTS POSSIBLE SEVERE THUNDERSTORMS THIS AFTERNOON.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BECAUSE OF
CLOUDINESS TODAY. USED AN AVERAGE OF THE NAM AND GFS FOR THE WIND
FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT SUPPORTS NUMEROUS
SHOWERS AND THUNDERSTORMS TONIGHT. LEANED TOWARD THE HIGHER POP
GUIDANCE. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING WILL
SUPPORT VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS.
SIGNIFICANT SHEAR MAY ALSO SUPPORT ORGANIZED THUNDERSTORMS WITH
DAMAGING WIND POSSIBLE. THE THREAT OF SEVERE THUNDERSTORMS SHOULD
DIMINISH LATE BECAUSE OF DIMINISHED INSTABILITY ASSOCIATED WITH
PREVIOUS CONVECTION AND NOCTURNAL COOLING. THE NAM AND GFS KEEP
THE FRONT NEAR THE FORECAST AREA WEDNESDAY AND WEDNESDAY NIGHT BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA. THE GFS MOS
INDICATED LOWER POPS COMPARED TO THE NAM AND MAY BE CORRECT
BECAUSE OF THE DIMINISHED MOISTURE AND WIDESPREAD CONVECTION THAT
SHOULD HAVE OCCURRED EARLIER. HOWEVER...BASED ON THE FRONT
LINGERING IN THE AREA AND ANOTHER MID-LEVEL SHORTWAVE TROUGH WE
MAINTAINED CHANCE POPS. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE GFS AND ECMWF GENERALLY SHOWED AN ONSHORE FLOW INTO THE
FORECAST AREA ASSOCIATED WITH HIGH PRESSURE CENTERED OFF THE
MIDDLE ATLANTIC COAST. THERE MAY BE A WEAKNESS IN THE UPPER
RIDGING DURING MUCH OF THE PERIOD. EXPECT SCATTERED MAINLY DIURNAL
THUNDERSTORMS WITH TEMPERATURES NEAR CLIMATOLOGY. THE GFS AND
ECMWF MOS PLUS GFS ENSEMBLE MEANS SUPPORT CHANCE POPS AND NORMAL
TEMPERATURES.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
MOST OF THE CONVECTIVE ACTIVITY HAS MOVED EAST OF THE FORECAST AREA
EARLY THIS MORNING. CONCERN WILL NOW SHIFT TO ANY FOG/STRATUS
POTENTIAL. RAINFALL HAS OCCURRED AT ALL THE TERMINALS AND CURRENT
DEWPOINT DEPRESSIONS LOW. HOWEVER...LATEST CAE VAD WIND PROFILE
INDICATING A SW 20 TO 25 KT LOW LEVEL JET...AND SATELLITE SUGGESTS
CONSIDERABLE UPPER LEVEL CONVECTIVE DEBRIS CLOUD COVER COULD
LINGER...WHICH WOULD WORK AGAINST FOG FORMATION. LATEST HIGH RES
MODEL GUIDANCE SUGGESTING LOWER CLOUDS POSSIBLE WITH MVFR TO IFR
CIGS. FOR NOW...WILL INDICATE PERIOD OF IFR OR BRIEF LIFR CONDITIONS
DURING THE PRE-DAWN HOURS.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED TO POSSIBLY NUMEROUS MAINLY AFTERNOON/EVENING
THUNDERSTORMS.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 05Z-11Z. NO TAF AMENDMENTS ARE SCHEDULED FOR AGS DURING
THAT TIME. AVIATION INTERESTS ARE ADVISED THAT AGS TENDS TO BE A FOG
PRONE LOCATION...ALSO OFTEN EXPERIENCING VARIABLE CONDITIONS.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 180700
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
300 AM EDT TUE JUN 18 2013
.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.
&&
.NEAR TERM /THROUGH TODAY/...
HIGH MOISTURE WILL CONTINUE TODAY AHEAD OF THE SLOW MOVING FRONT.
CONVERGENCE ASSOCIATED WITH THE FRONT...HEATING...PLUS ANOTHER IN
A SERIES OF MID-LEVEL SHORTWAVE TROUGHS SHOULD SUPPORT NUMEROUS
SHOWERS AND THUNDERSTORMS. THE HIGH RESOLUTION MODELS SUPPORT THE
GREATEST COVERAGE IN THE AFTERNOON. PRECIPITABLE WATER AROUND 2
INCHES AND POSSIBLE TRAINING SUPPORT VERY HEAVY RAIN WITH SOME OF
THE THUNDERSTORMS. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
DISPLAYS SURFACE-BASED LI/S -3 TO -4 TODAY. HOWEVER...BOTH THE NAM
AND ESPECIALLY THE GFS SHOW SIGNIFICANT SHEAR. THE NAM SHOWS H85
WIND INCREASING TO 25 TO 30 KNOTS. THE GFS DISPLAYS 35 TO 40
KNOTS. THE GFS MAY BE OVERDONE...BUT IT HAS SUPPORT FROM THE 12Z
YESTERDAY RUN OF THE ECMWF. HEAVY PRECIPITATION LOADING AND THE
SHEAR SUPPORTS POSSIBLE SEVERE THUNDERSTORMS THIS AFTERNOON.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BECAUSE OF
CLOUDINESS TODAY. USED AN AVERAGE OF THE NAM AND GFS FOR THE WIND
FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT SUPPORTS NUMEROUS
SHOWERS AND THUNDERSTORMS TONIGHT. LEANED TOWARD THE HIGHER POP
GUIDANCE. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING WILL
SUPPORT VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS.
SIGNIFICANT SHEAR MAY ALSO SUPPORT ORGANIZED THUNDERSTORMS WITH
DAMAGING WIND POSSIBLE. THE THREAT OF SEVERE THUNDERSTORMS SHOULD
DIMINISH LATE BECAUSE OF DIMINISHED INSTABILITY ASSOCIATED WITH
PREVIOUS CONVECTION AND NOCTURNAL COOLING. THE NAM AND GFS KEEP
THE FRONT NEAR THE FORECAST AREA WEDNESDAY AND WEDNESDAY NIGHT BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA. THE GFS MOS
INDICATED LOWER POPS COMPARED TO THE NAM AND MAY BE CORRECT
BECAUSE OF THE DIMINISHED MOISTURE AND WIDESPREAD CONVECTION THAT
SHOULD HAVE OCCURRED EARLIER. HOWEVER...BASED ON THE FRONT
LINGERING IN THE AREA AND ANOTHER MID-LEVEL SHORTWAVE TROUGH WE
MAINTAINED CHANCE POPS. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE GFS AND ECMWF GENERALLY SHOWED AN ONSHORE FLOW INTO THE
FORECAST AREA ASSOCIATED WITH HIGH PRESSURE CENTERED OFF THE
MIDDLE ATLANTIC COAST. THERE MAY BE A WEAKNESS IN THE UPPER
RIDGING DURING MUCH OF THE PERIOD. EXPECT SCATTERED MAINLY DIURNAL
THUNDERSTORMS WITH TEMPERATURES NEAR CLIMATOLOGY. THE GFS AND
ECMWF MOS PLUS GFS ENSEMBLE MEANS SUPPORT CHANCE POPS AND NORMAL
TEMPERATURES.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
CONVECTIVE ACTIVITY HAS DIMINISHED. EXPECT MOST CONVECTIVE
ACTIVITY TO DISSIPATE DURING THE EARLY MORNING HOURS AFTER AN
UPPER DISTURBANCE MOVES THROUGH. CONCERN WILL THEN SHIFT TO ANY
FOG/STRATUS POTENTIAL. RAINFALL HAS OCCURRED AT ALL THE TERMINALS
AND CURRENT DEWPOINT DEPRESSIONS LOW. HOWEVER...LATEST CAE VAD
WIND PROFILE INDICATING A SW 25 KT LOW LEVEL JET...AND SATELLITE
SUGGESTS CONSIDERABLE UPPER LEVEL CONVECTIVE DEBRIS CLOUD COVER
COULD LINGER...WHICH WOULD WORK AGAINST FOG FORMATION. LATEST HIGH
RES MODEL GUIDANCE SUGGESTING LOWER CLOUDS POSSIBLE WITH MVFR TO
IFR CIGS. FOR NOW...WILL INDICATE PERIOD OF MVFR CONDITIONS LATE
TONIGHT/EARLY TUESDAY MORNING.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED TO POSSIBLY NUMEROUS MAINLY AFTERNOON/EVENING
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 180622
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
222 AM EDT TUE JUN 18 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
10 PM UPDATE...CLUSTER OF STORMS IN THE CENTRAL PART OF THE CWFA
HOLDING THEIR OWN AND PRODUCING WIDESPREAD HEAVY RAINFALL. LATEST
RAP RUN SEEMS TO HAVE PICKED UP ON THIS CLUSTER EARLIER IN ITS
EVOLUTION BUT SHOWS IT DIMINISHING OVER THE NEXT COUPLE OF HOURS.
MESOANALYSIS SHOWS LESSER INSTABILITY OUT AHEAD OF THE CLUSTER...AND
RECENT TRENDS IN COMPOSITE REFLECTIVITY SUGGEST IT IS LOSING STEAM.
OTHERWISE...POPS HAVE BEEN LOWERED TO SCHC UNTIL CLOSER TO DAYBREAK
WHEN BETTER MOISTURE AND FORCING MOVE IN FROM THE WEST.
PREV DISCUSSION...
THIS AFTERNOON THROUGH TONIGHT...THE OVERALL CONV COVERAGE IS
BEGINNING TO PICK UP ACROSS THE CWFA WITH A DEFINITE MINIMA SEEN
OVER THE UPSTATE AND FAR ERN ZONES. SOME CELLS HAVE BECOME FAIRLY
STRONG AND A COUPLE COULD REACH SEVERE CRITERIA...MAINLY FOR LARGE
HAIL...AS THE AFTERNOON PROGRESSES. THE UPPER LEVEL VORT ACTIVITY IS
RATHER WEAK AND ILL DEFINED OVER THE CWFA...BUT WILL COUNT ON
GENERAL EASTWARD DEVELOPMENT OF STORMS THROUGH THE EVENING. THINGS
WILL BEGIN TO WANE AFT SUNSET AND LOSS OF SBCAPE...HOWEVER UPPER
POCKETS OF PVA WILL TRAVERSE THE DEEPLY MOIST AIRMASS AND ISOL/SCT
-SHRA/TSTMS ARE NOT OUT OF THE QUESTION THROUGH DAYBREAK. MIN TEMPS
WILL BE HELD A COUPLE CATS OR SO ABOVE NORMAL IN THIS ENVIRONMENT.
A SHARPENING H5 S/W WILL MOVE INTO TN TOMORROW AND CREATE A GOOD
AMOUNT OF DYNAMIC OMEGA...ABOUT TWICE AS MUCH VV/S AS TODAY.
THUS...WILL ANTICIPATE GOOD COVERAGE OF SHOWERS AND STORMS EARLY
ON...ESP ACROSS THE NC MTNS WHERE CAT POPS ARE ADVERTISED AFT 15Z.
DEEP LAYERED SHEAR WILL BE ABOUT 10 KTS HIGHER TOMORROW...BUT SBCAPE
MAY ACTUALLY BE LOWER DUE TO ALL THE CLOUD COVER. YET...STILL THINK
A BETTER POTENTIAL EXISTS FOR SVR STORMS TOMORROW AFTERNOON AS THE
DEFINED S/W CROSSES OVERHEAD DURING MAX HEATING. MAX TEMPS WILL BE
SIMILAR TO TODAY/S...OR RIGHT AROUND NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AT 215 PM EDT MON...THERE IS GOOD MODEL CONSENSUS THAT A WEAK AREA
OF LOW PRESSURE AND ASSOCIATED WEAK COLD FRONT WILL CROSS THE AREA
FROM WEST TO EAST TUE NIGHT. HOWEVER...THERE ARE SOME MINOR TIMING
DIFFERENCES. THE 12Z GFS IS A LITTEL STRONGER WITH THE SURFACE LOW
AND FASTER WITH THE SYSTEMS MOVEMENT. THE 12Z NAM IS SIMILAR TO THE
SREF IN REGARD TO TIMING...SO HAVE LEANED MORE TOWARD A NAM
SOLUTION. HENCE...WE EXPECT NUMEROUS SHOWERS/THUNDERSTORMS TO AFFECT
THE WESTERN CAROLINAS AND NE GA TUE NIGHT. THE HIGHEST QPF AND POPS
SHOULD BE OVER NORTHERN SECTIONS CLOSER TO THE BEST UPPER FORCING.
WITH PWATS AROUND 2 INCHES...SOME LOCALLY HEAVY RAIN IS CERTAINLY A
POSSIBILITY. HOWEVER...DO NOT BELIEVE THAT THE FLOOD THREAT IS MORE
THAN ISOLATED AT THIS POINT.
ON WED...THE FRONT IS FORECAST TO MOVE EAST OF THE I-77 CORRIDOR
DURING THE MORNING. HENCE...WILL HAVE SCATTERED POPS IN THAT AREA
EARLY...BUT WILL TAKE THE MENTION OF PRECIP OUT OF THE FORECAST BY
MIDDAY. ON WED AFTERNOON...THE GFS AND THE CMC BRING WINDS
AROUND TO AN UPSLOPE COMPONENT OVER THE MOUNTAINS AND RESPOND WITH
SOME QPF THERE. THE NAM IS ESSENTIALLY DRY. WILL COMPROMISE AT THIS
POINT WITH JUST SOME VERY LOW END POPS OVER THE MOUNTAINS.
WITH CONTINUING LIGHT UPSLOPE FLOW ADVERTISED BY THE GLOBAL MODELS
WED NIGHT...CAN`T RULE OUT AT LEAST SOME WIDELY SCATTERED SHOWERS
CONTINUING OVER THE MOUNTAINS. ON THU...EXPECT THAT SCATTERED SHOWERS
AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS DURING THE
AFTERNOON AS THE WEAK UPSLOPE FLOW CONTINUES ALONG WITH WEAKLY
DIVERGENT FLOW ALOFT. USED THE ALL-BLEND GUIDANCE WHICH KEEPS MAX
TEMPS A CATEGORY OR SO BELOW AVERAGE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 110 PM EDT MONDAY...HEIGHTS WILL SLOWLY BUILD FROM THE WEST
FROM THURSDAY NIGHT INTO THE WEEKEND AS THE CENTER OF THE UPPER
RIDGE SHIFTS EAST FROM TEXAS TO SOMEWHERE OVER THE SE
STATES...DEPENDING ON WHICH MODEL YOU REFERENCE. A LIGHT EASTERLY
LOW LEVEL FLOW FRIDAY AND SATURDAY WILL SHIFT TO LIGHT SOUTHWEST BY
LATE SUNDAY INTO MONDAY. LIGHT WIND ALL THE WAY UP TO AROUND 500MB
WITH AROUND 10 KTS AT 500MB AND GENERALLY LESS DOWN TO THE SURFACE
FROM DAY 5 THROUGH NEW DAY 7. SURFACE HIGH PRESSURE CENTERED NEAR
NEW JERSEY THURSDAY NIGHT WILL RIDGE DOWN THROUGH THE CAROLINAS WITH
THE COOLER THAN NORMAL TEMPERATURES. THE CENTER OF THIS HIGH WILL
DRIFT TO NEAR BERMUDA LATE IN THE WEEKEND AND EARLY NEXT WEEK
PROVIDING A CHANGE IN AIRMASS COMBINED WITH INCREASING INFLUENCE OF
THE UPPER RIDGE BUILDING FROM THE WEST. CAPE VALUES ON FRIDAY AND
SATURDAY WILL BE A LITTLE HIGHER OVER THE MTNS...1000 TO 1600 ON THE
GFS FRIDAY. CAPE VALUES DROP OFF VERY LOW SUNDAY AND MONDAY. VARYING
LEVELS OF LOW LEVEL MOISTURE THROUGHOUT THE MEDIUM RANGE WILL SERVE
FOR THE PRODUCTION OF PM SHOWERS AND T-STORMS. TEMPERATURES A BIT
WARMER AT END OF THE WEEKEND AND START OF NEXT WEEK.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
AT KCLT...BORDERLINE VFR/MVFR CONDITIONS WILL PREVAIL THROUGH THE
OVERNIGHT HOURS BEFORE CIGS GRADUALLY LOWER TO SOLID MVFR LEVELS.
AS UPPER LEVEL SHORT WAVE TROF APPROACHES AROUND MID MORNING...AMPLE
MOISTURE IN THE BOUNDARY LAYER WILL PROMPT A REORGANIZATION OF OVC
MVFR CIGS AND SCATTERED SHOWER DEVELOPMENT. PRECIPITATION COVERAGE
WILL CONTINUE TO INCREASE THROUGH THE LATE MORNING HOURS ACROSS THE
REGION THUS STARTED WITH VCSH AND GAVE WAY TO -SHRA BY AROUND 14Z.
CIGS WILL INCREASE TO VFR LEVELS LATE TOMORROW MORNING AS THE
ATMOSPHERE HEATS. FURTHERMORE...INCREASING INSTABILITY THROUGH THE
COLUMN...AND CONVERGENCE ALONG A PASSING FRONTAL BOUNDARY WILL ALLOW
FOR SOME THUNDERSTORM DEVELOPMENT TOMORROW AFTERNOON. WITH
THAT...INCLUDED A PROB30 GROUP FROM 18-24Z FOR MVFR VISB WITH
TSRA. THE FRONT WILL LIKELY NOT REACH KCLT UNTIL AROUND THE 02Z
TIMEFRAME SHIFTING WINDS TO A NORTHERLY COMPONENT. WINDS ALONG AND
JUST AHEAD OF THE FRONT COULD BE GUSTY WITH READINGS IN THE 20KT
RANGE NOT BEING OUT OF THE QUESTION.
ELSEWHERE...PREVAILED LOW END MVFR CIGS THROUGH THE FIRST PERIOD OF
THE TAF CYCLE DUE TO CONVECTIVE CLOUD DEBRIS ACROSS THE REGION.
BEYOND THAT...CIGS WILL RAISE SLIGHTLY ON TUESDAY MORNING BUT
SHOULD REMAIN AT MVFR LEVELS. CIGS WILL FINALLY REBOUND TO VFR
CONDITIONS LATE MORNING AS THE BOUNDARY LAYER WARMS.
FURTHERMORE...KEPT SOME MENTION OF VCSH AT ALL SITES AS SCATTERED
LIGHT SHOWERS CONTINUE ACROSS THE REGION. BY MID TO LATE
MORNING...UPPER LEVEL SHORTWAVE WILL MOVE IN...AND INSTABILITY WILL
HAVE INCREASED SOMEWHAT ALLOWING FOR SOME THUNDERSTORM ACTIVITY TO
DEVELOP. THE WINDOW FOR THUNDERSTORMS LOOKS TO BE A LITTLE NARROWER
FOR THE SOUTH CAROLINA SITES..THUS HANDLED THEM WITH TEMP GROUPS.
FOR KAVL AND KHKY...DECIDE TO GO WITH A PROB30 AS MODEL GUIDANCE
INDICATES INSTABILITY SHOULD REMAIN HIGHER LATER INTO THE DAY AS THE
FRONT APPROACHES. NEAR THE END OF THE PERIOD...THE FRONT WILL MOVE
THROUGH WESTERN NORTH CAROLINA BY AROUND 00Z...AND CONTINUE PUSHING
TO THE SOUTHEAST REACHING THE SOUTH CAROLINA SITES BY AROUND 03-04Z
WEDNESDAY. WINDS ALONG AND JUST AHEAD OF THE FRONT COULD BE GUSTY
WITH READINGS IN THE 20KT RANGE NOT BEING OUT OF THE QUESTION.
OUTLOOK...CONDITIONS WILL IMPROVE SOMEWHAT TUE NIGHT AS DRIER AIR
FILLS IN BEHIND A COLD FRONT. A MODERATELY UNSTABLE ATMOSPHERE
COMBINED WITH EASTERLY FLOW MAY LEAD TO SHOWER AND THUNDERSTORM
DEVELOPMENT MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 83% HIGH 91% HIGH 100% HIGH 93%
KGSP HIGH 81% HIGH 88% HIGH 96% HIGH 94%
KAVL HIGH 86% HIGH 91% HIGH 91% HIGH 80%
KHKY HIGH 88% HIGH 80% HIGH 92% HIGH 90%
KGMU MED 72% HIGH 96% HIGH 96% HIGH 89%
KAND HIGH 85% HIGH 81% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...DEO
AVIATION...CDG
000
FXUS62 KCHS 180532
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
132 AM EDT TUE JUN 18 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLUSTERS OF SHOWERS/TSTMS ARE APPROACHING THE CHARLESTON TRI-
COUNTY AREA FROM THE SW AND WILL IMPACT MUCH OF THE METRO AREA
THROUGH 3 AM. LOCALLY HEAVY RAINFALL...GUSTY WINDS AND CLOUD TO
GROUND LIGHTNING WILL ACCOMPANY THESE STORM. MODIFIED POPS TO
MATCH GOING TRENDS. THE BULK OF THE RAINFALL SHOULD MOVE OUT OF
THE LOCAL FORECAST AREA BY 5 AM OR SO...BUT A RISK FOR MEASURABLE
RAINFALL WILL LINGER THROUGH SUNRISE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
TUESDAY...SFC HIGH PRESSURE WILL GRADUALLY BREAK DOWN EARLY AS A SFC
LOW TRACKS OVER THE TENNESSEE VALLEY AND TO THE MID ATLANTIC STATES.
SOUTHWEST FLOW AHEAD OF THE SFC LOW WILL LIKELY CONTRIBUTE TO
INCREASING LOW LVL MOISTURE OVER THE SOUTHEAST WHILE A SERIES OF H5
SHORTWAVES BEGIN TO SWING AROUND THE SOUTHERN PERIPHERY OF A BROAD
MID LVL TROUGH CENTERED NORTHEAST OF THE GREAT LAKES. CHANCES OF
SHOWERS/THUNDERSTORMS SHOULD INCREASE IN COVERAGE DURING THE
AFTERNOON AS TEMPS WARM INTO THE MID/UPPER 80S...ESPECIALLY FOR
INLAND LOCATIONS. GIVEN SFC DEWPTS IN THE LOW 70S...PWATS NEAR 2.0
INCHES...AND WEAK MID/UPPER LVL FLOW...EXPECT PULSE TYPE
THUNDERSTORMS CAPABLE OF PRODUCING BRIEF WIND GUSTS AND HEAVY
RAINFALL. SHOWER/THUNDERSTORM ACTIVITY SHOULD CONTINUE THROUGH THE
OVERNIGHT PERIOD AS A SFC COLD FRONT APPROACHES FROM THE
WEST/NORTHWEST LATE. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE
LOW/MID 70S.
WEDNESDAY AND THURSDAY...A SFC COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WEDNESDAY MORNING
BEFORE GRADUALLY STALLING OVER OR JUST SOUTH OF THE REGION ON
THURSDAY. AS THIS OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL
FORCING SHOULD FAVOR A PERIOD OF SHOWERS/THUNDERSTORMS EARLY
WEDNESDAY WITH COLD FROPA BEFORE ACTIVITY SHIFTS SOUTH OVER GEORGIA
ZONES ON THURSDAY. SHOWERS/THUNDERSTORMS MAY PRODUCE HEAVY RAINFALL
GIVEN THE AMOUNT OF MOISTURE AND WEAK WINDS IN PLACE. GREATEST
COVERAGE OF ACTIVITY WILL LIKELY BE ALONG OR NEAR THE FRONT
WEDNESDAY MORNING...WITH A 40-60 PERCENT CHANCE OF PRECIPITATION. BY
THURSDAY...CHANCES OF PRECIP SHOULD BEGIN TO DECLINE OVER SC ZONES
WHILE THE FRONT STALLS AND WEAKENS SOUTH OF INTERSTATE 16 IN
GEORGIA. HAVE MAINTAINED 30-40 POPS OVER THE REGION THURSDAY WITH
HIGHEST CHANCES FOR SOUTHERN GA ZONES. OVERALL HIGH TEMPS ARE
EXPECTED TO PEAK IN THE MID/UPPER 80S OVER MOST LOCATIONS
WEDNESDAY...WITH SLIGHTLY COOLER TEMPS IN THE MID 80S OVER SOUTH
CAROLINA ON THURSDAY BEHIND THE FRONT. WEDNESDAY NIGHT LOWS ARE
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
TSTMS WILL MOVE ACROSS THE KCHS TERMINAL 06-08Z BRINGING GUSTY
WINDS AND LOCALIZED IFR VSBYS. THE NEAR TERM RISK FOR TSTMS SHOULD
END BY 08Z WITH A RETURN TO VFR CONDITIONS. VFR WILL DOMINATE AT
KSAV THROUGH SUNRISE WITH THE BULK OF THE TSTMS ACTIVITY PASSING
TO THE NORTH OF THAT TERMINAL. HIGH RESOLUTION MODELS SHOW ANOTHER
BATCH OF SHOWERS/TSTMS MOVING ACROSS THE COASTAL CORRIDOR BY LATE
MORNING AFTERNOON AS A POTENT SHORTWAVE PUSHES THROUGH. WILL
CARRY TEMPO GROUPS FOR 4SM TSRA BR BKN040CB FROM 18-21Z AT KCHS
AND 16-19Z AT KSAV TO COVER. ADJUSTMENTS WILL MOST CERTAINLY BE
NEEDED AS THE MORNING PROGRESSES.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS TUESDAY THROUGH
THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA...MAINLY DURING AFTERNOON HOURS.
&&
.MARINE...
TONIGHT...SOUTHERLY WINDS WILL INCREASE SLIGHTLY AHEAD OF AN
APPROACHING COLD FRONT FAR UPSTREAM. SPEEDS COULD REACH AS HIGH
AS 15 TO 20 KT AT TIMES WITH SEAS BUILDING TO 2 TO 4 FT...HIGHEST
BEYOND 20 NM.
TUESDAY THROUGH FRIDAY...WINDS/SEAS WILL LIKELY REMAIN BELOW SMALL
CRAFT ADVISORY THRESHOLDS FOR MUCH OF THE DAY TUESDAY BEFORE
INCREASING TUESDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS BETWEEN
HIGH PRESSURE OVER THE WESTERN ATLANTIC AND A SFC COLD FRONT
APPROACHING THE WATERS FROM THE WEST/NORTHWEST LATE. AS A
RESULT...SOUTH/SOUTHWEST FLOW IS ANTICIPATED TO SURGE TUESDAY NIGHT
WITH 20-25 KT WINDS AND SEAS UP TO 5 FT BEYOND 20 NM. EXPECT WIND
DIRECTIONS TO VEER WEST/NORTHWEST AS THE FRONT STEADILY SLIPS OVER
THE WATERS WEDNESDAY INTO THURSDAY...WITH WIND SPEEDS DIMINISHING AS
THE FRONT WEAKENS/STALLS. NUMERICAL MODEL SOLUTIONS DIFFER REGARDING
THE PRECISE LOCATION OF THE STALLING FRONT...BUT WILL LEAN TOWARD
PERSISTENCE IN INDICATING A GENERAL EAST/NORTHEAST FLOW FOR THURSDAY
AND FRIDAY. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY
CONDITIONS THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
000
FXUS62 KCAE 180525
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
125 AM EDT TUE JUN 18 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL BE PUMPING PLENTY OF
MOISTURE INTO THE SOUTHEASTERN U.S. A WEAK FRONTAL ZONE MOVING SLOWLY
EASTWARD TOWARD THE FORECAST AREA WILL COMBINE WITH THE ATLANTIC
MOISTURE AND PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
MUCH OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
TONIGHT...EXPECT SCATTERED SHOWERS AND SOME THUNDERSTORMS
OVERNIGHT. THE ACTIVITY SHOULD WEAKEN BECAUSE OF NOCTURNAL
COOLING. PRECIPITABLE WATER VALUES WILL REMAIN HIGH SO ANY
ACTIVITY CAN PRODUCE BRIEF LOCALLY HEAVY RAINS. LOW TEMPERATURES
WILL BE MAINLY IN THE LOWER 70S.
TUESDAY...HEATING...PLENTY OF MOISTURE...AND A SERIES OF UPPER-
LEVEL DISTURBANCES WILL INCREASE SHOWER AND THUNDERSTORM ACTIVITY
AGAIN ON TUESDAY...MAINLY IN THE AFTERNOON. TEMPS WILL RISE INTO
THE MID 80S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
LINGERING MOISTURE ASSOCIATED WITH AN EAST-WEST ORIENTED FRONT
WILL CONTINUE TO AFFECT THE REGION. THE MODELS KEEP BROAD UPPER-
LEVEL TROUGHING WITH A SERIES OF SHORTWAVE TROUGHS MOVING THROUGH
THE FLOW OVER THE FORECAST AREA. THIS WILL CONTINUE THE CHANCE FOR
SHOWER AND THUNDERSTORM DEVELOPMENT. KEPT HIGH TEMPERATURES BELOW
GUIDANCE WITH THE EXPECTED RAIN AND CLOUDINESS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
SURFACE HIGH PRESSURE BEGINS TO BUILD DOWN INTO THE CAROLINAS ON
THURSDAY AND THE CHANCE OF SHOWERS AND THUNDERSTORMS LESSENS INTO
THE WEEKEND BUT THERE REMAINS ENOUGH MOISTURE FOR POSSIBLE AFTERNOON
SHOWERS AND THUNDERSTORMS. EXPECT HIGH TEMPERATURES NEAR OR A LITTLE
BELOW CLIMATOLOGY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
CONVECTIVE ACTIVITY HAS WEAKENED SOMEWHAT OVER THE PAST COUPLE OF
HOURS. CURRENT RADAR INDICATES SHOWER ACTIVITY WILL AFFECT MAINLY
THE CSRA AND SOUTHERN MIDLANDS...INCLUDING AGS/DNL/OGB...OVER THE
NEXT COUPLE OF HOURS. WILL EXPECT MOST CONVECTIVE ACTIVITY TO
DISSIPATE DURING THE EARLY MORNING HOURS AFTER AN UPPER DISTURBANCE
MOVES THROUGH. CONCERN WILL THEN SHIFT TO ANY FOG/STRATUS POTENTIAL.
RAINFALL HAS OCCURRED AT ALL THE TERMINALS AND CURRENT DEWPOINT
DEPRESSIONS LOW. HOWEVER...LATEST CAE VAD WIND PROFILE INDICATING A
SW 25 KT LOW LEVEL JET...AND SATELLITE SUGGESTS CONSIDERABLE
UPPER LEVEL CONVECTIVE DEBRIS CLOUD COVER COULD LINGER...WHICH WOULD
WORK AGAINST FOG FORMATION. LATEST HIGH RES MODEL GUIDANCE
SUGGESTING LOWER CLOUDS POSSIBLE WITH MVFR TO IFR CIGS. FOR
NOW...WILL INDICATE PERIOD OF MVFR CONDITIONS LATE TONIGHT/EARLY
TUESDAY MORNING.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED TO POSSIBLY NUMEROUS MAINLY AFTERNOON/EVENING
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 180325
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1125 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL BE PUMPING PLENTY OF
MOISTURE INTO THE SOUTHEASTERN U.S. A WEAK FRONTAL ZONE MOVING SLOWLY
EASTWARD TOWARD THE FORECAST AREA WILL COMBINE WITH THE ATLANTIC
MOISTURE AND PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
MUCH OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
TONIGHT...EXPECT SCATTERED SHOWERS AND SOME THUNDERSTORMS
OVERNIGHT. THE ACTIVITY SHOULD WEAKEN BECAUSE OF NOCTURNAL
COOLING. PRECIPITABLE WATER VALUES WILL REMAIN HIGH SO ANY
ACTIVITY CAN PRODUCE BRIEF LOCALLY HEAVY RAINS. LOW TEMPERATURES
WILL BE MAINLY IN THE LOWER 70S.
TUESDAY...HEATING...PLENTY OF MOISTURE...AND A SERIES OF UPPER-
LEVEL DISTURBANCES WILL INCREASE SHOWER AND THUNDERSTORM ACTIVITY
AGAIN ON TUESDAY...MAINLY IN THE AFTERNOON. TEMPS WILL RISE INTO
THE MID 80S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
LINGERING MOISTURE ASSOCIATED WITH AN EAST-WEST ORIENTED FRONT
WILL CONTINUE TO AFFECT THE REGION. THE MODELS KEEP BROAD UPPER-
LEVEL TROUGHING WITH A SERIES OF SHORTWAVE TROUGHS MOVING THROUGH
THE FLOW OVER THE FORECAST AREA. THIS WILL CONTINUE THE CHANCE FOR
SHOWER AND THUNDERSTORM DEVELOPMENT. KEPT HIGH TEMPERATURES BELOW
GUIDANCE WITH THE EXPECTED RAIN AND CLOUDINESS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
SURFACE HIGH PRESSURE BEGINS TO BUILD DOWN INTO THE CAROLINAS ON
THURSDAY AND THE CHANCE OF SHOWERS AND THUNDERSTORMS LESSENS INTO
THE WEEKEND BUT THERE REMAINS ENOUGH MOISTURE FOR POSSIBLE AFTERNOON
SHOWERS AND THUNDERSTORMS. EXPECT HIGH TEMPERATURES NEAR OR A LITTLE
BELOW CLIMATOLOGY.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
MAIN FOCUS AT THIS TIME WILL BE THUNDERSTORM ACTIVITY IN THE NEAR
TERM. CURRENT RADAR INDICATES THUNDERSTORM ACTIVITY WILL AFFECT
MAINLY THE CSRA AND SOUTHERN MIDLANDS...INCLUDING AGS/DNL/OGB...OVER
THE NEXT FEW HOURS. WILL EXPECT MOST CONVECTIVE ACTIVITY TO
DISSIPATE LATER TONIGHT AFTER AN UPPER DISTURBANCE MOVES THROUGH.
CONCERN WILL THEN SHIFT TO ANY FOG/STRATUS POTENTIAL. RAINFALL HAS
OCCURRED AT ALL THE TERMINALS AND CURRENT DEWPOINT DEPRESSIONS LOW.
HOWEVER...BUFKIT INDICATES A SW 30 TO 35 KT LOW LEVEL JET
TONIGHT...AND SATELLITE SUGGESTS CONSIDERABLE UPPER LEVEL CONVECTIVE
DEBRIS CLOUD COVER COULD LINGER...WHICH WOULD WORK AGAINST FOG
FORMATION. LATEST HIGH RES MODEL GUIDANCE SUGGESTING LOWER CLOUDS
POSSIBLE WITH MVFR TO IFR CIGS. FOR NOW...WILL INDICATE PERIOD OF
MVFR CONDITIONS LATE TONIGHT/EARLY TUESDAY MORNING.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED TO POSSIBLY NUMEROUS MAINLY AFTERNOON/EVENING
THUNDERSTORMS.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 03Z-11Z. NO TAF AMENDMENTS ARE SCHEDULED FOR AGS DURING
THAT TIME. AVIATION INTERESTS ARE ADVISED THAT AGS TENDS TO BE A FOG
PRONE LOCATION...ALSO OFTEN EXPERIENCING VARIABLE CONDITIONS.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 180240
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1040 PM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
10 PM UPDATE...CLUSTER OF STORMS IN THE CENTRAL PART OF THE CWFA
HOLDING THEIR OWN AND PRODUCING WIDESPREAD HEAVY RAINFALL. LATEST
RAP RUN SEEMS TO HAVE PICKED UP ON THIS CLUSTER EARLIER IN ITS
EVOLUTION BUT SHOWS IT DIMINISHING OVER THE NEXT COUPLE OF HOURS.
MESOANALYSIS SHOWS LESSER INSTABILITY OUT AHEAD OF THE CLUSTER...AND
RECENT TRENDS IN COMPOSITE REFLECTIVITY SUGGEST IT IS LOSING STEAM.
OTHERWISE...POPS HAVE BEEN LOWERED TO SCHC UNTIL CLOSER TO DAYBREAK
WHEN BETTER MOISTURE AND FORCING MOVE IN FROM THE WEST.
PREV DISCUSSION...
THIS AFTERNOON THROUGH TONIGHT...THE OVERALL CONV COVERAGE IS
BEGINNING TO PICK UP ACROSS THE CWFA WITH A DEFINITE MINIMA SEEN
OVER THE UPSTATE AND FAR ERN ZONES. SOME CELLS HAVE BECOME FAIRLY
STRONG AND A COUPLE COULD REACH SEVERE CRITERIA...MAINLY FOR LARGE
HAIL...AS THE AFTERNOON PROGRESSES. THE UPPER LEVEL VORT ACTIVITY IS
RATHER WEAK AND ILL DEFINED OVER THE CWFA...BUT WILL COUNT ON
GENERAL EASTWARD DEVELOPMENT OF STORMS THROUGH THE EVENING. THINGS
WILL BEGIN TO WANE AFT SUNSET AND LOSS OF SBCAPE...HOWEVER UPPER
POCKETS OF PVA WILL TRAVERSE THE DEEPLY MOIST AIRMASS AND ISOL/SCT
-SHRA/TSTMS ARE NOT OUT OF THE QUESTION THROUGH DAYBREAK. MIN TEMPS
WILL BE HELD A COUPLE CATS OR SO ABOVE NORMAL IN THIS ENVIRONMENT.
A SHARPENING H5 S/W WILL MOVE INTO TN TOMORROW AND CREATE A GOOD
AMOUNT OF DYNAMIC OMEGA...ABOUT TWICE AS MUCH VV/S AS TODAY.
THUS...WILL ANTICIPATE GOOD COVERAGE OF SHOWERS AND STORMS EARLY
ON...ESP ACROSS THE NC MTNS WHERE CAT POPS ARE ADVERTISED AFT 15Z.
DEEP LAYERED SHEAR WILL BE ABOUT 10 KTS HIGHER TOMORROW...BUT SBCAPE
MAY ACTUALLY BE LOWER DUE TO ALL THE CLOUD COVER. YET...STILL THINK
A BETTER POTENTIAL EXISTS FOR SVR STORMS TOMORROW AFTERNOON AS THE
DEFINED S/W CROSSES OVERHEAD DURING MAX HEATING. MAX TEMPS WILL BE
SIMILAR TO TODAY/S...OR RIGHT AROUND NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AT 215 PM EDT MON...THERE IS GOOD MODEL CONSENSUS THAT A WEAK AREA
OF LOW PRESSURE AND ASSOCIATED WEAK COLD FRONT WILL CROSS THE AREA
FROM WEST TO EAST TUE NIGHT. HOWEVER...THERE ARE SOME MINOR TIMING
DIFFERENCES. THE 12Z GFS IS A LITTEL STRONGER WITH THE SURFACE LOW
AND FASTER WITH THE SYSTEMS MOVEMENT. THE 12Z NAM IS SIMILAR TO THE
SREF IN REGARD TO TIMING...SO HAVE LEANED MORE TOWARD A NAM
SOLUTION. HENCE...WE EXPECT NUMEROUS SHOWERS/THUNDERSTORMS TO AFFECT
THE WESTERN CAROLINAS AND NE GA TUE NIGHT. THE HIGHEST QPF AND POPS
SHOULD BE OVER NORTHERN SECTIONS CLOSER TO THE BEST UPPER FORCING.
WITH PWATS AROUND 2 INCHES...SOME LOCALLY HEAVY RAIN IS CERTAINLY A
POSSIBILITY. HOWEVER...DO NOT BELIEVE THAT THE FLOOD THREAT IS MORE
THAN ISOLATED AT THIS POINT.
ON WED...THE FRONT IS FORECAST TO MOVE EAST OF THE I-77 CORRIDOR
DURING THE MORNING. HENCE...WILL HAVE SCATTERED POPS IN THAT AREA
EARLY...BUT WILL TAKE THE MENTION OF PRECIP OUT OF THE FORECAST BY
MIDDAY. ON WED AFTERNOON...THE GFS AND THE CMC BRING WINDS
AROUND TO AN UPSLOPE COMPONENT OVER THE MOUNTAINS AND RESPOND WITH
SOME QPF THERE. THE NAM IS ESSENTIALLY DRY. WILL COMPROMISE AT THIS
POINT WITH JUST SOME VERY LOW END POPS OVER THE MOUNTAINS.
WITH CONTINUING LIGHT UPSLOPE FLOW ADVERTISED BY THE GLOBAL MODELS
WED NIGHT...CAN`T RULE OUT AT LEAST SOME WIDELY SCATTERED SHOWERS
CONTINUING OVER THE MOUNTAINS. ON THU...EXPECT THAT SCATTERED SHOWERS
AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS DURING THE
AFTERNOON AS THE WEAK UPSLOPE FLOW CONTINUES ALONG WITH WEAKLY
DIVERGENT FLOW ALOFT. USED THE ALL-BLEND GUIDANCE WHICH KEEPS MAX
TEMPS A CATEGORY OR SO BELOW AVERAGE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 110 PM EDT MONDAY...HEIGHTS WILL SLOWLY BUILD FROM THE WEST
FROM THURSDAY NIGHT INTO THE WEEKEND AS THE CENTER OF THE UPPER
RIDGE SHIFTS EAST FROM TEXAS TO SOMEWHERE OVER THE SE
STATES...DEPENDING ON WHICH MODEL YOU REFERENCE. A LIGHT EASTERLY
LOW LEVEL FLOW FRIDAY AND SATURDAY WILL SHIFT TO LIGHT SOUTHWEST BY
LATE SUNDAY INTO MONDAY. LIGHT WIND ALL THE WAY UP TO AROUND 500MB
WITH AROUND 10 KTS AT 500MB AND GENERALLY LESS DOWN TO THE SURFACE
FROM DAY 5 THROUGH NEW DAY 7. SURFACE HIGH PRESSURE CENTERED NEAR
NEW JERSEY THURSDAY NIGHT WILL RIDGE DOWN THROUGH THE CAROLINAS WITH
THE COOLER THAN NORMAL TEMPERATURES. THE CENTER OF THIS HIGH WILL
DRIFT TO NEAR BERMUDA LATE IN THE WEEKEND AND EARLY NEXT WEEK
PROVIDING A CHANGE IN AIRMASS COMBINED WITH INCREASING INFLUENCE OF
THE UPPER RIDGE BUILDING FROM THE WEST. CAPE VALUES ON FRIDAY AND
SATURDAY WILL BE A LITTLE HIGHER OVER THE MTNS...1000 TO 1600 ON THE
GFS FRIDAY. CAPE VALUES DROP OFF VERY LOW SUNDAY AND MONDAY. VARYING
LEVELS OF LOW LEVEL MOISTURE THROUGHOUT THE MEDIUM RANGE WILL SERVE
FOR THE PRODUCTION OF PM SHOWERS AND T-STORMS. TEMPERATURES A BIT
WARMER AT END OF THE WEEKEND AND START OF NEXT WEEK.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
AT KCLT...WHILE -RA MAY LINGER FOR A COUPLE OF HOURS TO START THE
PERIOD...IT APPEARS THUNDER ACTIVITY WILL REMAIN WEST AND SOUTH OF
THE FIELD THIS EVENING. FEW-SCT CLOUDS BELOW 040 WILL BE SEEN THIS
EVENING AS LEFTOVERS FROM ONGOING TS. LIGHT SWLY WINDS ALOFT WILL
BRING IN MORE MOISTURE OVERNIGHT AND SHOULD DEVELOP A LOWER CIG.
GUIDANCE WIDELY DIFFERS ON CATEGORY...BUT RAW NAM SEEMS MOST
PLAUSIBLE IN LIGHT OF MOISTURE PROFILES AND THIS MORNING/S UPSTREAM
CIGS. THIS KEEPS MVFR...BUT TOWARD LOW SIDE. PRECIP CHANCES RAMP
BACK UP EARLY WITH UNSTABLE ATMOSPHERE AHEAD OF INCOMING FRONT.
-SHRA AFTER 15Z WITH TS CERTAINLY POSSIBLE...THOUGH HIGHLIGHTED
AFTERNOON IN A PROB30 WITH MVFR EFFECTS. WOULD NOT BE SURPRISED IF
IFR RESULTED IN SOME OF THE HEAVIER SHOWERS GIVEN ALL THE MOISTURE.
WINDS ALOFT PICK UP AHEAD OF THE FRONT AND GUSTS TO 20 KT LIKELY TO
MIX DOWN BY AFTN.
ELSEWHERE...TS AND SHRA WILL MAINLY FOCUS TONIGHT ALONG AXIS JUST TO
THE SOUTH OF OUR FORECAST AREA...ACROSS CENTRAL GA AND SC. A FEW TS
ARE ALSO OCCURRING IN THE MTNS. THIS ACTIVITY WILL CONTINUE THIS
EVENING BUT GRADUALLY DIMINISH. TEMPO FOR TS AT KAVL THRU 02Z.
SUFFICIENT DEEP MOISTURE AND FORCING ALOFT TO EXPECT SOME SHOWERS TO
BE ABLE TO POP UP OVERNIGHT. TS LESS LIKELY SO HANDLED CHANCES WITH
VCSH FOR THE MOST PART. THE INCREASING MOISTURE WILL LIKELY LEAD TO
A DEVELOPING MVFR CIG OVER MUCH OF THE AREA...BUT ESPECIALLY IN THE
MTNS WHERE PATCHY IFR MAY ALSO RESULT. FRONTAL PASSAGE LOOKS TO
OCCUR TOMORROW DURING PEAK OF AFTERNOON INSTABILITY SO TS LIKELY TO
BREAK OUT. FOR NOW HAVE INCLUDED VCTS AS NEEDED. GUSTY WINDS OF 15
TO 20 KT WILL DEVELOP IN THE STRENGTHENING FLOW AHEAD OF THE FRONT.
FROPA WILL CAUSE A NW SHIFT AT KAVL BY AFTN...BUT TOO LATE TO BE
REFLECTED IN TAFS FURTHER SOUTH AND EAST. OTHERWISE GENERALLY S TO
SW.
OUTLOOK...CONDITIONS WILL IMPROVE SOMEWHAT TUE NIGHT AS DRIER AIR
FILLS IN BEHIND A COLD FRONT...BUT SOME RESTRICTIONS ARE STILL
POSSIBLE IN THE MTNS WED MORNING. A MODERATELY UNSTABLE ATMOSPHERE
COMBINED WITH EASTERLY FLOW MAY LEAD TO SHOWER AND THUNDERSTORM
DEVELOPMENT MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 99% HIGH 87% HIGH 81% HIGH 100%
KGSP HIGH 87% HIGH 84% HIGH 100% MED 74%
KAVL HIGH 100% HIGH 86% MED 75% MED 70%
KHKY HIGH 94% HIGH 87% HIGH 92% LOW 58%
KGMU HIGH 100% HIGH 83% MED 63% MED 66%
KAND HIGH 100% HIGH 85% HIGH 90% HIGH 95%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...DEO
AVIATION...SBK/WIMBERLEY
000
FXUS62 KCAE 180226
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1026 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL BE PUMPING PLENTY OF
MOISTURE INTO THE SOUTHEASTERN U.S. A WEAK FRONTAL ZONE MOVING SLOWLY
EASTWARD TOWARD THE PALMETTO STATE WILL COMBINE WITH THE ATLANTIC
MOISTURE AND PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
MUCH OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
TONIGHT...EXPECT SCATTERED SHOWERS AND SOME THUNDERSTORMS OVER THE
EASTERN HALF OF THE FORECAST AREA. THE ACTIVITY SHOULD WEAKEN
AFTER MIDNIGHT. PRECIPITABLE WATER VALUES WILL REMAIN HIGH SO ANY
ACTIVITY CAN PRODUCE BRIEF LOCALLY HEAVY RAINS. LOW TEMPERATURES
MAINLY WILL BE MAINLY IN THE LOWER 70S. HEATING...PLENTY OF
MOISTURE...AND A SERIES OF UPPER LEVEL DISTURBANCES WILL INCREASE
SHOWER AND THUNDERSTORM ACTIVITY AGAIN ON TUESDAY...MAINLY IN THE
AFTERNOON. TEMPS WILL RISE INTO THE MID 80S.
&&
.SHORT TERM /TUESDAY NIGHT/...
LINGERING MOISTURE ASSOCIATED WITH AN EAST-WEST ORIENTED FRONT WILL
CONTINUE TO AFFECT THE REGION. THE MODELS KEEP BROAD UPPER-LEVEL
TROUGH WITH A SERIES OF SHORTWAVES MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. THIS WILL CONTINUE THE CHANCE FOR SHOWER AND
THUNDERSTORM DEVELOPMENT TUESDAY AND TUESDAY NIGHT AND INTO
WEDNESDAY. KEPT TEMPERATURES BELOW GUIDANCE WITH THE EXPECTED RAIN
AND CLOUDINESS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
SURFACE HIGH PRESSURE BEGINS TO BUILD DOWN INTO THE CAROLINAS ON
THURSDAY AND THE CHANCE OF SHOWERS AND THUNDERSTORMS LESSENS INTO
THE WEEKEND BUT THERE REMAINS ENOUGH MOISTURE FOR POSSIBLE AFTERNOON
SHOWERS AND THUNDERSTORMS. EXPECT HIGH TEMPERATURES NEAR OR A LITTLE
BELOW CLIMATOLOGY.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
MAIN FOCUS AT THIS TIME WILL BE THUNDERSTORM ACTIVITY IN THE NEAR
TERM. CURRENT RADAR INDICATES THUNDERSTORM ACTIVITY WILL AFFECT
MAINLY THE CSRA AND SOUTHERN MIDLANDS...INCLUDING AGS/DNL/OGB...OVER
THE NEXT FEW HOURS. WILL EXPECT MOST CONVECTIVE ACTIVITY TO
DISSIPATE LATER TONIGHT AFTER AN UPPER DISTURBANCE MOVES THROUGH.
CONCERN WILL THEN SHIFT TO ANY FOG/STRATUS POTENTIAL. RAINFALL HAS
OCCURRED AT ALL THE TERMINALS AND CURRENT DEWPOINT DEPRESSIONS LOW.
HOWEVER...BUFKIT INDICATES A SW 30 TO 35 KT LOW LEVEL JET
TONIGHT...AND SATELLITE SUGGESTS CONSIDERABLE UPPER LEVEL CONVECTIVE
DEBRIS CLOUD COVER COULD LINGER...WHICH WOULD WORK AGAINST FOG
FORMATION. LATEST HIGH RES MODEL GUIDANCE SUGGESTING LOWER CLOUDS
POSSIBLE WITH MVFR TO IFR CIGS. FOR NOW...WILL INDICATE PERIOD OF
MVFR CONDITIONS LATE TONIGHT/EARLY TUESDAY MORNING.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED TO POSSIBLY NUMEROUS MAINLY AFTERNOON/EVENING
THUNDERSTORMS.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 03Z-11Z. NO TAF AMENDMENTS ARE SCHEDULED FOR AGS DURING
THAT TIME. AVIATION INTERESTS ARE ADVISED THAT AGS TENDS TO BE A FOG
PRONE LOCATION...ALSO OFTEN EXPERIENCING VARIABLE CONDITIONS.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 180202
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1002 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
WATER VAPOR IMAGERY SHOWS EVIDENCE OF UPPER LEVEL ENERGY PUSHING
EASTWARD DOWNSTREAM OF A SHORTWAVE TROUGH STRETCHING FROM THE OHIO
VALLEY THROUGH THE SOUTHERN PLAINS. MESOANALYSIS ALSO INDICATES A
MESO LOW ACROSS SOUTH CENTRAL GEORGIA AND EVEN SOME LINGERING
INSTABILITY ACROSS THE SOUTHEAST GEORGIA ZONES BY 9 PM EDT.
SCATTERED CONVECTION THUS CONTINUES ACROSS PORTIONS OF THE
FORECAST AREA THIS EVENING...DRIVEN BY BOUNDARY INTERACTIONS AND
MAINTAINED BY THE AFOREMENTIONED WEAK INSTABILITY. THE STRONGEST
THUNDERSTORMS ARE CURRENTLY FROM A LINE SHIFTING INTO THE FAR
WEST/SOUTHWEST ZONES WHERE INSTABILITY AND FORCING ARE MAXIMIZED.
ALTHOUGH AN ISOLATED STRONG THUNDERSTORM IS STILL POSSIBLE BEFORE
MIDNIGHT...EXPECT POTENTIAL FOR SEVERE STORMS TO CONTINUE TO
DIMINISH AS THE NIGHT PROGRESSES.
SHORT RANGE MODEL SOLUTIONS HAVE STRUGGLED TO DEPICT THE COVERAGE
AND EVOLUTION OF LATE EVENING CONVECTION...AND HAVE THUS HAD TO
ADJUST POP SCHEME ACCORDING TO SHORT TERM TRENDS. WILL KEEP
ANOTHER HOUR OR TWO OF LIKELY THUNDERSTORM POTENTIAL FOR THE
WESTERN TIER ZONES...MAINTAINING SOLID CHANCE POPS IN THE 40 TO 50
PERCENT RANGE ELSEWHERE...EXCEPT SOUTH OF INTERSTATE 16 WHERE
THUNDERSTORM POTENTIAL IS DOWN TO JUST A SLIGHT CHANCE.
THE GRADUAL EASTWARD SHIFT OF THE MAIN SHORTWAVE TROUGH...ALONG
WITH THE APPROACH/INTENSIFICATION OF A SURFACE WAVE OF LOW
PRESSURE INTO THE TENNESSEE VALLEY...WILL PULL DEEP MOISTURE
SLIGHTLY NORTH AFTER MIDNIGHT. MODEL SOLUTIONS SUGGEST A GENERAL
DIMINISHING IN CONVECTIVE COVERAGE AND INTENSITY FROM SOUTH TO
NORTH TOWARD THE PRE DAWN HOURS. ALTHOUGH DETAILS ARE STILL
UNCERTAIN AND ADJUSTMENTS WILL LIKELY BE NEEDED...HAVE REDUCED
PRECIPITATION CHANCES TO AROUND 30 PERCENT NORTHERN TIER TO BELOW
15 PERCENT NEAR THE ALTAMAHA BY DAYBREAK TUESDAY.
CONSIDERING THE ABUNDANT RAINFALL ACROSS THE AREA THIS AFTERNOON
AND EVENING...WILL NEED TO MONITOR WIND SPEEDS OVERNIGHT. IF WINDS
BECOME LIGHT TO CALM...FOG COULD BE AN ISSUE LATE. HOURLY
TEMPERATURES HAVE BEEN IMPACTED BY PASSING
SHOWERS/THUNDERSTORMS...YET THE ONGOING FORECAST FOR NIGHTTIME
LOWS STILL LOOKS ON TRACK. EXPECT TEMPERATURES TO COOL INTO THE
LOWER 70S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...SFC HIGH PRESSURE WILL GRADUALLY BREAK DOWN EARLY AS A SFC
LOW TRACKS OVER THE TENNESSEE VALLEY AND TO THE MID ATLANTIC STATES.
SOUTHWEST FLOW AHEAD OF THE SFC LOW WILL LIKELY CONTRIBUTE TO
INCREASING LOW LVL MOISTURE OVER THE SOUTHEAST WHILE A SERIES OF H5
SHORTWAVES BEGIN TO SWING AROUND THE SOUTHERN PERIPHERY OF A BROAD
MID LVL TROUGH CENTERED NORTHEAST OF THE GREAT LAKES. CHANCES OF
SHOWERS/THUNDERSTORMS SHOULD INCREASE IN COVERAGE DURING THE
AFTERNOON AS TEMPS WARM INTO THE MID/UPPER 80S...ESPECIALLY FOR
INLAND LOCATIONS. GIVEN SFC DEWPTS IN THE LOW 70S...PWATS NEAR 2.0
INCHES...AND WEAK MID/UPPER LVL FLOW...EXPECT PULSE TYPE
THUNDERSTORMS CAPABLE OF PRODUCING BRIEF WIND GUSTS AND HEAVY
RAINFALL. SHOWER/THUNDERSTORM ACTIVITY SHOULD CONTINUE THROUGH THE
OVERNIGHT PERIOD AS A SFC COLD FRONT APPROACHES FROM THE
WEST/NORTHWEST LATE. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE
LOW/MID 70S.
WEDNESDAY AND THURSDAY...A SFC COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WEDNESDAY MORNING
BEFORE GRADUALLY STALLING OVER OR JUST SOUTH OF THE REGION ON
THURSDAY. AS THIS OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL
FORCING SHOULD FAVOR A PERIOD OF SHOWERS/THUNDERSTORMS EARLY
WEDNESDAY WITH COLD FROPA BEFORE ACTIVITY SHIFTS SOUTH OVER GEORGIA
ZONES ON THURSDAY. SHOWERS/THUNDERSTORMS MAY PRODUCE HEAVY RAINFALL
GIVEN THE AMOUNT OF MOISTURE AND WEAK WINDS IN PLACE. GREATEST
COVERAGE OF ACTIVITY WILL LIKELY BE ALONG OR NEAR THE FRONT
WEDNESDAY MORNING...WITH A 40-60 PERCENT CHANCE OF PRECIPITATION. BY
THURSDAY...CHANCES OF PRECIP SHOULD BEGIN TO DECLINE OVER SC ZONES
WHILE THE FRONT STALLS AND WEAKENS SOUTH OF INTERSTATE 16 IN
GEORGIA. HAVE MAINTAINED 30-40 POPS OVER THE REGION THURSDAY WITH
HIGHEST CHANCES FOR SOUTHERN GA ZONES. OVERALL HIGH TEMPS ARE
EXPECTED TO PEAK IN THE MID/UPPER 80S OVER MOST LOCATIONS
WEDNESDAY...WITH SLIGHTLY COOLER TEMPS IN THE MID 80S OVER SOUTH
CAROLINA ON THURSDAY BEHIND THE FRONT. WEDNESDAY NIGHT LOWS ARE
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
A SWATH OF SHOWERS MOVING NORTHWARD TOWARD THE KCHS TERMINAL COULD
SUPPORT TEMPORARY SHRA UNTIL AROUND 04Z. EXPECT WANING CONVECTIVE
COVERAGE AS THE NIGHT PROGRESSES...AND WILL THUS KEEP CONDITIONS
PREVAILING VFR. HOWEVER...FLIGHT RESTRICTIONS IN STRATUS/FOG
SUPPORTED BY ABUNDANT RAINFALL AND TRAPPED LOW LEVEL MOISTURE
COULD BECOME AN ISSUE...AND TRENDS WILL NEED TO BE CLOSELY
MONITORED DURING THE NEXT FEW HOURS. DIURNAL SHOWERS/THUNDERSTORMS
WILL REDEVELOP TUESDAY...ESPECIALLY DURING THE AFTERNOON. HOWEVER A
PRECISE FORECAST OF TIMING AND IMPACTS WILL NOT BE POSSIBLE WITHIN
THE 00Z TAFS.
EXTENDED AVIATION...EXTENDED AVIATION...PERIODIC FLIGHT
RESTRICTIONS TUESDAY THROUGH THURSDAY IN ASSOCIATION WITH
SCATTERED TO NUMEROUS SHRA/TSRA...MAINLY DURING AFTERNOON HOURS.
&&
.MARINE...
TONIGHT...SOUTHERLY WINDS WILL INCREASE SLIGHTLY AHEAD OF AN
APPROACHING COLD FRONT FAR UPSTREAM. SPEEDS COULD REACH AS HIGH
AS 15 TO 20 KT AT TIMES WITH SEAS BUILDING TO 2 TO 4 FT...HIGHEST
BEYOND 20 NM.
TUESDAY THROUGH FRIDAY...WINDS/SEAS WILL LIKELY REMAIN BELOW SMALL
CRAFT ADVISORY THRESHOLDS FOR MUCH OF THE DAY TUESDAY BEFORE
INCREASING TUESDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS BETWEEN
HIGH PRESSURE OVER THE WESTERN ATLANTIC AND A SFC COLD FRONT
APPROACHING THE WATERS FROM THE WEST/NORTHWEST LATE. AS A
RESULT...SOUTH/SOUTHWEST FLOW IS ANTICIPATED TO SURGE TUESDAY NIGHT
WITH 20-25 KT WINDS AND SEAS UP TO 5 FT BEYOND 20 NM. EXPECT WIND
DIRECTIONS TO VEER WEST/NORTHWEST AS THE FRONT STEADILY SLIPS OVER
THE WATERS WEDNESDAY INTO THURSDAY...WITH WIND SPEEDS DIMINISHING AS
THE FRONT WEAKENS/STALLS. NUMERICAL MODEL SOLUTIONS DIFFER REGARDING
THE PRECISE LOCATION OF THE STALLING FRONT...BUT WILL LEAN TOWARD
PERSISTENCE IN INDICATING A GENERAL EAST/NORTHEAST FLOW FOR THURSDAY
AND FRIDAY. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY
CONDITIONS THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...DPB/RJB
LONG TERM...WMS
AVIATION...SPR/WMS
MARINE...SPR/DPB
000
FXUS62 KGSP 180013
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
813 PM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
7 PM UPDATE...TRAINING CELLS PRODUCING HIGH RAIN RATES ARE ALIGNED
JUST TO OUR SOUTH...BUT CLOSE ENOUGH TO THINK SOME CONTINUED TSTM
ACTIVITY WILL OCCUR ALONG OUR SE BORDER ZONES. ADDITIONAL ACTIVITY
OVER THE WRN MTNS AND FOOTHILLS WILL LIKELY PERSIST FOR AT LEAST
ANOTHER HOUR OR TWO BEFORE INSTABILITY DIMINISHES. ALSO THESE CELLS
MAY SUFFER DUE TO THEIR INFLOW MOISTURE BEING CONSUMED BY THE
AFOREMENTIONED ACTIVITY TO OUR SOUTH. WHILE THESE AREAS OF PRECIP
SHOULD AFFECT THE AREA LESS AND LESS TONIGHT...THERE REMAINS REASON
TO BELIEVE CHC POPS GIVEN THE MOIST PROFILES AND CYCLONIC FLOW
ALOFT...SO POPS STABILIZE IN CHC RANGE LATE.
PREV DISCUSSION...
THIS AFTERNOON THROUGH TONIGHT...THE OVERALL CONV COVERAGE IS
BEGINNING TO PICK UP ACROSS THE CWFA WITH A DEFINITE MINIMA SEEN
OVER THE UPSTATE AND FAR ERN ZONES. SOME CELLS HAVE BECOME FAIRLY
STRONG AND A COUPLE COULD REACH SEVERE CRITERIA...MAINLY FOR LARGE
HAIL...AS THE AFTERNOON PROGRESSES. THE UPPER LEVEL VORT ACTIVITY IS
RATHER WEAK AND ILL DEFINED OVER THE CWFA...BUT WILL COUNT ON
GENERAL EASTWARD DEVELOPMENT OF STORMS THROUGH THE EVENING. THINGS
WILL BEGIN TO WANE AFT SUNSET AND LOSS OF SBCAPE...HOWEVER UPPER
POCKETS OF PVA WILL TRAVERSE THE DEEPLY MOIST AIRMASS AND ISOL/SCT
-SHRA/TSTMS ARE NOT OUT OF THE QUESTION THROUGH DAYBREAK. MIN TEMPS
WILL BE HELD A COUPLE CATS OR SO ABOVE NORMAL IN THIS ENVIRONMENT.
A SHARPENING H5 S/W WILL MOVE INTO TN TOMORROW AND CREATE A GOOD
AMOUNT OF DYNAMIC OMEGA...ABOUT TWICE AS MUCH VV/S AS TODAY.
THUS...WILL ANTICIPATE GOOD COVERAGE OF SHOWERS AND STORMS EARLY
ON...ESP ACROSS THE NC MTNS WHERE CAT POPS ARE ADVERTISED AFT 15Z.
DEEP LAYERED SHEAR WILL BE ABOUT 10 KTS HIGHER TOMORROW...BUT SBCAPE
MAY ACTUALLY BE LOWER DUE TO ALL THE CLOUD COVER. YET...STILL THINK
A BETTER POTENTIAL EXISTS FOR SVR STORMS TOMORROW AFTERNOON AS THE
DEFINED S/W CROSSES OVERHEAD DURING MAX HEATING. MAX TEMPS WILL BE
SIMILAR TO TODAY/S...OR RIGHT AROUND NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AT 215 PM EDT MON...THERE IS GOOD MODEL CONSENSUS THAT A WEAK AREA
OF LOW PRESSURE AND ASSOCIATED WEAK COLD FRONT WILL CROSS THE AREA
FROM WEST TO EAST TUE NIGHT. HOWEVER...THERE ARE SOME MINOR TIMING
DIFFERENCES. THE 12Z GFS IS A LITTEL STRONGER WITH THE SURFACE LOW
AND FASTER WITH THE SYSTEMS MOVEMENT. THE 12Z NAM IS SIMILAR TO THE
SREF IN REGARD TO TIMING...SO HAVE LEANED MORE TOWARD A NAM
SOLUTION. HENCE...WE EXPECT NUMEROUS SHOWERS/THUNDERSTORMS TO AFFECT
THE WESTERN CAROLINAS AND NE GA TUE NIGHT. THE HIGHEST QPF AND POPS
SHOULD BE OVER NORTHERN SECTIONS CLOSER TO THE BEST UPPER FORCING.
WITH PWATS AROUND 2 INCHES...SOME LOCALLY HEAVY RAIN IS CERTAINLY A
POSSIBILITY. HOWEVER...DO NOT BELIEVE THAT THE FLOOD THREAT IS MORE
THAN ISOLATED AT THIS POINT.
ON WED...THE FRONT IS FORECAST TO MOVE EAST OF THE I-77 CORRIDOR
DURING THE MORNING. HENCE...WILL HAVE SCATTERED POPS IN THAT AREA
EARLY...BUT WILL TAKE THE MENTION OF PRECIP OUT OF THE FORECAST BY
MIDDAY. ON WED AFTERNOON...THE GFS AND THE CMC BRING WINDS
AROUND TO AN UPSLOPE COMPONENT OVER THE MOUNTAINS AND RESPOND WITH
SOME QPF THERE. THE NAM IS ESSENTIALLY DRY. WILL COMPROMISE AT THIS
POINT WITH JUST SOME VERY LOW END POPS OVER THE MOUNTAINS.
WITH CONTINUING LIGHT UPSLOPE FLOW ADVERTISED BY THE GLOBAL MODELS
WED NIGHT...CAN`T RULE OUT AT LEAST SOME WIDELY SCATTERED SHOWERS
CONTINUING OVER THE MOUNTAINS. ON THU...EXPECT THAT SCATTERED SHOWERS
AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS DURING THE
AFTERNOON AS THE WEAK UPSLOPE FLOW CONTINUES ALONG WITH WEAKLY
DIVERGENT FLOW ALOFT. USED THE ALL-BLEND GUIDANCE WHICH KEEPS MAX
TEMPS A CATEGORY OR SO BELOW AVERAGE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 110 PM EDT MONDAY...HEIGHTS WILL SLOWLY BUILD FROM THE WEST
FROM THURSDAY NIGHT INTO THE WEEKEND AS THE CENTER OF THE UPPER
RIDGE SHIFTS EAST FROM TEXAS TO SOMEWHERE OVER THE SE
STATES...DEPENDING ON WHICH MODEL YOU REFERENCE. A LIGHT EASTERLY
LOW LEVEL FLOW FRIDAY AND SATURDAY WILL SHIFT TO LIGHT SOUTHWEST BY
LATE SUNDAY INTO MONDAY. LIGHT WIND ALL THE WAY UP TO AROUND 500MB
WITH AROUND 10 KTS AT 500MB AND GENERALLY LESS DOWN TO THE SURFACE
FROM DAY 5 THROUGH NEW DAY 7. SURFACE HIGH PRESSURE CENTERED NEAR
NEW JERSEY THURSDAY NIGHT WILL RIDGE DOWN THROUGH THE CAROLINAS WITH
THE COOLER THAN NORMAL TEMPERATURES. THE CENTER OF THIS HIGH WILL
DRIFT TO NEAR BERMUDA LATE IN THE WEEKEND AND EARLY NEXT WEEK
PROVIDING A CHANGE IN AIRMASS COMBINED WITH INCREASING INFLUENCE OF
THE UPPER RIDGE BUILDING FROM THE WEST. CAPE VALUES ON FRIDAY AND
SATURDAY WILL BE A LITTLE HIGHER OVER THE MTNS...1000 TO 1600 ON THE
GFS FRIDAY. CAPE VALUES DROP OFF VERY LOW SUNDAY AND MONDAY. VARYING
LEVELS OF LOW LEVEL MOISTURE THROUGHOUT THE MEDIUM RANGE WILL SERVE
FOR THE PRODUCTION OF PM SHOWERS AND T-STORMS. TEMPERATURES A BIT
WARMER AT END OF THE WEEKEND AND START OF NEXT WEEK.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AT KCLT...WHILE -RA MAY LINGER FOR A COUPLE OF HOURS TO START THE
PERIOD...IT APPEARS THUNDER ACTIVITY WILL REMAIN WEST AND SOUTH OF
THE FIELD THIS EVENING. FEW-SCT CLOUDS BELOW 040 WILL BE SEEN THIS
EVENING AS LEFTOVERS FROM ONGOING TS. LIGHT SWLY WINDS ALOFT WILL
BRING IN MORE MOISTURE OVERNIGHT AND SHOULD DEVELOP A LOWER CIG.
GUIDANCE WIDELY DIFFERS ON CATEGORY...BUT RAW NAM SEEMS MOST
PLAUSIBLE IN LIGHT OF MOISTURE PROFILES AND THIS MORNING/S UPSTREAM
CIGS. THIS KEEPS MVFR...BUT TOWARD LOW SIDE. PRECIP CHANCES RAMP
BACK UP EARLY WITH UNSTABLE ATMOSPHERE AHEAD OF INCOMING FRONT.
-SHRA AFTER 15Z WITH TS CERTAINLY POSSIBLE...THOUGH HIGHLIGHTED
AFTERNOON IN A PROB30 WITH MVFR EFFECTS. WOULD NOT BE SURPRISED IF
IFR RESULTED IN SOME OF THE HEAVIER SHOWERS GIVEN ALL THE MOISTURE.
WINDS ALOFT PICK UP AHEAD OF THE FRONT AND GUSTS TO 20 KT LIKELY TO
MIX DOWN BY AFTN.
ELSEWHERE...TS AND SHRA WILL MAINLY FOCUS TONIGHT ALONG AXIS JUST TO
THE SOUTH OF OUR FORECAST AREA...ACROSS CENTRAL GA AND SC. A FEW TS
ARE ALSO OCCURRING IN THE MTNS. THIS ACTIVITY WILL CONTINUE THIS
EVENING BUT GRADUALLY DIMINISH. TEMPO FOR TS AT KAVL THRU 02Z.
SUFFICIENT DEEP MOISTURE AND FORCING ALOFT TO EXPECT SOME SHOWERS TO
BE ABLE TO POP UP OVERNIGHT. TS LESS LIKELY SO HANDLED CHANCES WITH
VCSH FOR THE MOST PART. THE INCREASING MOISTURE WILL LIKELY LEAD TO
A DEVELOPING MVFR CIG OVER MUCH OF THE AREA...BUT ESPECIALLY IN THE
MTNS WHERE PATCHY IFR MAY ALSO RESULT. FRONTAL PASSAGE LOOKS TO
OCCUR TOMORROW DURING PEAK OF AFTERNOON INSTABILITY SO TS LIKELY TO
BREAK OUT. FOR NOW HAVE INCLUDED VCTS AS NEEDED. GUSTY WINDS OF 15
TO 20 KT WILL DEVELOP IN THE STRENGTHENING FLOW AHEAD OF THE FRONT.
FROPA WILL CAUSE A NW SHIFT AT KAVL BY AFTN...BUT TOO LATE TO BE
REFLECTED IN TAFS FURTHER SOUTH AND EAST. OTHERWISE GENERALLY S TO
SW.
OUTLOOK...CONDITIONS WILL IMPROVE SOMEWHAT TUE NIGHT AS DRIER AIR
FILLS IN BEHIND A COLD FRONT...BUT SOME RESTRICTIONS ARE STILL
POSSIBLE IN THE MTNS WED MORNING. A MODERATELY UNSTABLE ATMOSPHERE
COMBINED WITH EASTERLY FLOW MAY LEAD TO SHOWER AND THUNDERSTORM
DEVELOPMENT MIDWEEK...CAUSING SPOTTY RESTRICTIONS.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT HIGH 98% HIGH 91% HIGH 80% HIGH 100%
KGSP HIGH 95% HIGH 92% HIGH 87% HIGH 85%
KAVL HIGH 100% HIGH 85% MED 74% HIGH 88%
KHKY HIGH 95% HIGH 89% HIGH 93% HIGH 84%
KGMU HIGH 100% HIGH 95% MED 70% MED 76%
KAND HIGH 100% HIGH 87% HIGH 84% HIGH 96%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...DEO
AVIATION...SBK/WIMBERLEY
000
FXUS62 KCAE 172332
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
732 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
THIS EVENING...SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE
EVENING HOURS WILL PRODUCE SOME LOCALLY HEAVY RAIN FALLS AS PWAT
AROUND 1.90 INCHES. HOWEVER WITH THE STORMS MOVING AT AROUND 25
MPH LITTLE FLOODING ISSUES ARE EXPECTED. LITTLE SHEAR OVER THE
AREA WITH LI`S OF -2 TO -3 BECOMING MORE STABLE AFTER 02Z.
TONIGHT...MAINLY DIURNAL ACTIVITY BUT NAM BRINGS ANOTHER WEAK
IMPULSE TO THE REGION LATE TONIGHT AFTER MIDNIGHT. SO...PLAN ON
KEEPING AT LEAST SOME LOW CHANCE...SAY AROUND 30 PERCENT AFTER
MIDNIGHT. OTHERWISE...EXPECT LOW TEMPERATURES MAINLY IN THE LOWER
70S.
&&
.SHORT TERM /TUESDAY NIGHT/...
LINGERING MOISTURE ASSOCIATED WITH AN EAST-WEST ORIENTED FRONT WILL
CONTINUE TO AFFECT THE REGION. THE MODELS KEEP BROAD UPPER-LEVEL
TROUGH WITH A SERIES OF SHORTWAVES MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. THIS WILL CONTINUE THE CHANCE FOR SHOWER AND
THUNDERSTORM DEVELOPMENT TUESDAY AND TUESDAY NIGHT AND INTO
WEDNESDAY. KEPT TEMPERATURES BELOW GUIDANCE WITH THE EXPECTED RAIN
AND CLOUDINESS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
SURFACE HIGH PRESSURE BEGINS TO BUILD DOWN INTO THE CAROLINAS ON
THURSDAY AND THE CHANCE OF SHOWERS AND THUNDERSTORMS LESSENS INTO
THE WEEKEND BUT THERE REMAINS ENOUGH MOISTURE FOR POSSIBLE AFTERNOON
SHOWERS AND THUNDERSTORMS. EXPECT HIGH TEMPERATURES NEAR OR A LITTLE
BELOW CLIMATOLOGY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
MAIN FOCUS AT THIS TIME WILL BE THUNDERSTORM ACTIVITY IN THE NEAR
TERM. CURRENT RADAR INDICATES A BAND OF THUNDERSTORMS MOVING E
TOWARDS AGS/DNL. WILL HANDLE THREAT WITH TEMPO GROUP.
WILL EXPECT MOST CONVECTIVE ACTIVITY TO DISSIPATE BY LATE
EVENING/EARLY TONIGHT. CONCERN WILL THEN SHIFT TO ANY FOG/STRATUS
POTENTIAL. DESPITE ANY RAINFALL THAT HAS OCCURRED/OR MAY OCCUR AT
TERMINALS...BUFKIT INDICATES A SW 30 TO 35 KT LOW LEVEL JET
TONIGHT...WHICH WOULD WORK AGAINST FOG FORMATION. HOWEVER...AGS IS A
VERY FOG PRONE LOCATION AND AGS RECEIVED RAIN EARLIER TODAY.
SO...SOME FOG POTENTIAL EXISTS AT AGS. LATEST GUIDANCE ALSO
INDICATING SOME STRATUS POTENTIAL AT MOST TERMINALS. FOR NOW...WILL
INDICATE PERIOD OF MVFR CONDITIONS.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED AFTERNOON/EVENING THUNDERSTORMS.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 03Z-11Z. NO TAF AMENDMENTS WILL BE ISSUED FOR AGS DURING
THAT TIME.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 172309
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
709 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
THIS EVENING...SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE
EVENING HOURS WILL PRODUCE SOME LOCALLY HEAVY RAIN FALLS AS PWAT
AROUND 1.90 INCHES. HOWEVER WITH THE STORMS MOVING AT AROUND 25
MPH LITTLE FLOODING ISSUES ARE EXPECTED. LITTLE SHEAR OVER THE
AREA WITH LI`S OF -2 TO -3 BECOMING MORE STABLE AFTER 02Z.
TONIGHT...MAINLY DIURNAL ACTIVITY BUT NAM BRINGS ANOTHER WEAK
IMPULSE TO THE REGION LATE TONIGHT AFTER MIDNIGHT. SO...PLAN ON
KEEPING AT LEAST SOME LOW CHANCE...SAY AROUND 30 PERCENT AFTER
MIDNIGHT. OTHERWISE...EXPECT LOW TEMPERATURES MAINLY IN THE LOWER
70S.
&&
.SHORT TERM /TUESDAY NIGHT/...
LINGERING MOISTURE ASSOCIATED WITH AN EAST-WEST ORIENTED FRONT WILL
CONTINUE TO AFFECT THE REGION. THE MODELS KEEP BROAD UPPER-LEVEL
TROUGH WITH A SERIES OF SHORTWAVES MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. THIS WILL CONTINUE THE CHANCE FOR SHOWER AND
THUNDERSTORM DEVELOPMENT TUESDAY AND TUESDAY NIGHT AND INTO
WEDNESDAY. KEPT TEMPERATURES BELOW GUIDANCE WITH THE EXPECTED RAIN
AND CLOUDINESS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
SURFACE HIGH PRESSURE BEGINS TO BUILD DOWN INTO THE CAROLINAS ON
THURSDAY AND THE CHANCE OF SHOWERS AND THUNDERSTORMS LESSENS INTO
THE WEEKEND BUT THERE REMAINS ENOUGH MOISTURE FOR POSSIBLE AFTERNOON
SHOWERS AND THUNDERSTORMS. EXPECT HIGH TEMPERATURES NEAR OR A LITTLE
BELOW CLIMATOLOGY.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
MAIN FOCUS AT THIS TIME WILL BE THUNDERSTORM ACTIVITY IN THE NEAR
TERM. RAIN/THUNDERSTORMS AFFECTED ALL TERMINALS EARLIER TODAY.
CURRENT RADAR AT 2214Z INDICATES A BAND OF THUNDERSTORMS MOVING ENE
AWAY FROM CAE/CUB...WITH SOME ACTIVITY WELL WEST OF
AGS/DNL...MOVING EAST. AT THIS TIME..HANDLING THREAT WITH
VCTS APPEARS APPROPRIATE.
WILL EXPECT MOST CONVECTIVE ACTIVITY TO DISSIPATE BY LATE
EVENING/EARLY TONIGHT. CONCERN WILL THEN SHIFT TO ANY FOG/STRATUS
POTENTIAL. DESPITE ANY RAINFALL THAT MAY OCCUR AT TERMINALS...BUFKIT
INDICATES A SW 30 TO 35 KT LOW LEVEL JET TONIGHT...WHICH WOULD WORK
AGAINST FOG FORMATION. HOWEVER...AGS IS A VERY FOG PRONE LOCATION
AND AGS RECEIVED RAIN EARLIER TODAY. SO...SOME FOG POTENTIAL EXISTS
AT AGS. LATEST GUIDANCE ALSO INDICATING SOME STRATUS POTENTIAL.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED AFTERNOON/EVENING THUNDERSTORMS.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 03Z-11Z. NO TAF AMENDMENTS WILL BE ISSUED FOR AGS DURING
THAT TIME.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 172237
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
637 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
EARLY MONDAY EVENING...MULTICELL THUNDERSTORMS WERE ADVANCING
EAST ACROSS THE I-95 CORRIDOR. MOST LOCATIONS ALONG/EAST OF I-95
WILL RECEIVE MEASURABLE RAINFALL THROUGH EARLY EVENING...ALTHOUGH
WEAKER INSTABILITY TOWARD THE COAST AND DIURNAL STABILIZATION
AFTER SUNSET SHOULD CONTINUE TO SUPPORT A GENERAL WEAKENING
TREND. THE EXCEPTION WILL BE AREAS ALONG/SOUTH OF I-16 WHERE
HIGHER SBCAPES WILL SUPPORT AN ISOLATED THREAT FOR A BRIEF/PULSE
SEVERE THUNDERSTORM OR TWO WITH LOCALIZED DAMAGING WIND GUSTS
THROUGH THE EARLY EVENING.
MEANWHILE...ADDITIONAL CLUSTERS OF SHOWERS/THUNDERSTORMS WILL DEVELOP
ALONG MESOSCALE BOUNDARIES OVER/UPSTREAM OF THE FORECAST AREA THIS
EVENING/TONIGHT...BUT DIURNAL STABILIZATION SHOULD TRANSLATE TO
DECREASING CONVECTION COVERAGE/INTENSITY...THUS HIGHEST POPS THIS
EVENING WILL TAPER TO SLIGHT CHANCE/CHANCE LATER THIS EVENING AND
OVERNIGHT.
EXPECT ADDITIONAL ADJUSTMENTS TO POPS AS THE EVENING PROGRESSES.
GIVEN RAINFALL...WILL ALSO ASSESS THE POTENTIAL FOR FOG OVERNIGHT.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...SFC HIGH PRESSURE WILL GRADUALLY BREAK DOWN EARLY AS A SFC
LOW TRACKS OVER THE TENNESSEE VALLEY AND TO THE MID ATLANTIC STATES.
SOUTHWEST FLOW AHEAD OF THE SFC LOW WILL LIKELY CONTRIBUTE TO
INCREASING LOW LVL MOISTURE OVER THE SOUTHEAST WHILE A SERIES OF H5
SHORTWAVES BEGIN TO SWING AROUND THE SOUTHERN PERIPHERY OF A BROAD
MID LVL TROUGH CENTERED NORTHEAST OF THE GREAT LAKES. CHANCES OF
SHOWERS/THUNDERSTORMS SHOULD INCREASE IN COVERAGE DURING THE
AFTERNOON AS TEMPS WARM INTO THE MID/UPPER 80S...ESPECIALLY FOR
INLAND LOCATIONS. GIVEN SFC DEWPTS IN THE LOW 70S...PWATS NEAR 2.0
INCHES...AND WEAK MID/UPPER LVL FLOW...EXPECT PULSE TYPE
THUNDERSTORMS CAPABLE OF PRODUCING BRIEF WIND GUSTS AND HEAVY
RAINFALL. SHOWER/THUNDERSTORM ACTIVITY SHOULD CONTINUE THROUGH THE
OVERNIGHT PERIOD AS A SFC COLD FRONT APPROACHES FROM THE
WEST/NORTHWEST LATE. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE
LOW/MID 70S.
WEDNESDAY AND THURSDAY...A SFC COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WEDNESDAY MORNING
BEFORE GRADUALLY STALLING OVER OR JUST SOUTH OF THE REGION ON
THURSDAY. AS THIS OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL
FORCING SHOULD FAVOR A PERIOD OF SHOWERS/THUNDERSTORMS EARLY
WEDNESDAY WITH COLD FROPA BEFORE ACTIVITY SHIFTS SOUTH OVER GEORGIA
ZONES ON THURSDAY. SHOWERS/THUNDERSTORMS MAY PRODUCE HEAVY RAINFALL
GIVEN THE AMOUNT OF MOISTURE AND WEAK WINDS IN PLACE. GREATEST
COVERAGE OF ACTIVITY WILL LIKELY BE ALONG OR NEAR THE FRONT
WEDNESDAY MORNING...WITH A 40-60 PERCENT CHANCE OF PRECIPITATION. BY
THURSDAY...CHANCES OF PRECIP SHOULD BEGIN TO DECLINE OVER SC ZONES
WHILE THE FRONT STALLS AND WEAKENS SOUTH OF INTERSTATE 16 IN
GEORGIA. HAVE MAINTAINED 30-40 POPS OVER THE REGION THURSDAY WITH
HIGHEST CHANCES FOR SOUTHERN GA ZONES. OVERALL HIGH TEMPS ARE
EXPECTED TO PEAK IN THE MID/UPPER 80S OVER MOST LOCATIONS
WEDNESDAY...WITH SLIGHTLY COOLER TEMPS IN THE MID 80S OVER SOUTH
CAROLINA ON THURSDAY BEHIND THE FRONT. WEDNESDAY NIGHT LOWS ARE
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
SHOWERS/THUNDERSTORMS WILL IMPACT TERMINALS THIS EVENING...WITH
GREATEST IMPACTS AT KSAV. THEN...VFR CONDITIONS SHOULD PREVAIL
OVERNIGHT THROUGH TUESDAY MORNING...ALTHOUGH FLIGHT RESTRICTIONS
IN STRATUS/FOG PROMOTED BY RAINFALL/LOW LEVEL MOISTURE CANNOT BE
DISCOUNTED. DIURNAL SHOWERS/THUNDERSTORMS WILL REDEVELOP TUESDAY
ESPECIALLY DURING THE AFTERNOON BUT A PRECISE FORECAST OF TIMING
AND IMPACTS WILL NOT BE POSSIBLE WITHIN THE 00Z TAFS.
EXTENDED AVIATION...EXTENDED AVIATION...PERIODIC FLIGHT
RESTRICTIONS TUESDAY THROUGH THURSDAY IN ASSOCIATION WITH
SCATTERED TO NUMEROUS SHRA/TSRA...MAINLY DURING AFTERNOON HOURS.
&&
.MARINE...
TONIGHT...WHERE SHOWERS/THUNDERSTORMS PUSH INTO THE COASTAL WATERS
LIGHT/VARIABLE WINDS COULD DEVELOP FOR SEVERAL HOURS THIS EVENING.
OVERNIGHT...S WINDS WILL INCREASE SLIGHTLY AHEAD OF AN APPROACHING
COLD FRONT. SPEEDS COULD REACH AS HIGH AS 15-20 KT AT TIMES WITH
SEAS 2-4 FT...HIGHEST E.
TUESDAY THROUGH FRIDAY...WINDS/SEAS WILL LIKELY REMAIN BELOW SMALL
CRAFT ADVISORY THRESHOLDS FOR MUCH OF THE DAY TUESDAY BEFORE
INCREASING TUESDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS BETWEEN
HIGH PRESSURE OVER THE WESTERN ATLANTIC AND A SFC COLD FRONT
APPROACHING THE WATERS FROM THE WEST/NORTHWEST LATE. AS A
RESULT...SOUTH/SOUTHWEST FLOW IS ANTICIPATED TO SURGE TUESDAY NIGHT
WITH 20-25 KT WINDS AND SEAS UP TO 5 FT BEYOND 20 NM. EXPECT WIND
DIRECTIONS TO VEER WEST/NORTHWEST AS THE FRONT STEADILY SLIPS OVER
THE WATERS WEDNESDAY INTO THURSDAY...WITH WIND SPEEDS DIMINISHING AS
THE FRONT WEAKENS/STALLS. NUMERICAL MODEL SOLUTIONS DIFFER REGARDING
THE PRECISE LOCATION OF THE STALLING FRONT...BUT WILL LEAN TOWARD
PERSISTENCE IN INDICATING A GENERAL EAST/NORTHEAST FLOW FOR THURSDAY
AND FRIDAY. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY
CONDITIONS THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...SPR
SHORT TERM...DPB/RJB
LONG TERM...WMS
AVIATION...SPR
MARINE...DPB/SPR
000
FXUS62 KCAE 172214
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
614 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
THIS AFTERNOON...A WEAK SHORT WAVE WILL MOVE EASTWARD THROUGH
THE REGION THIS AFTERNOON. THIS MAY HELP TO TRIGGER SOME CONVECTIVE
ACTIVITY BUT EXPECT MAINLY JUST SCATTERED. A WEAKLY SHEARED
ENVIRONMENT WITH JUST MARGINAL LIS -2/-3...TOTALS 44/45 AND CAPES
LESS THAN 1000 J/KG. SOME HEAVY RAIN POSSIBLE IN SHOWERS AND
THUNDERSTORMS WITH PWAT AROUND 1.90 INCHES. SIX HOUR QPF VALUES
AROUND 0.10 OF AN INCH OR LESS. SO NOT MUCH FLOODING POTENTIAL
EXPECTED. AND LATEST SATELLITE PCPN ESTIMATE KEEPS FLOODING
POTENTIAL TO THE NORTH AND WEST IN THE LATEST SPENES.
TONIGHT...MAINLY DIURNAL ACTIVITY BUT NAM BRINGS ANOTHER WEAK
IMPULSE TO THE REGION LATE TONIGHT AFTER MIDNIGHT. SO...PLAN ON
KEEPING AT LEAST SOME LOW CHANCE...SAY AROUND 30 PERCENT AFTER
MIDNIGHT. OTHERWISE...EXPECT LOW TEMPERATURES MAINLY IN THE
LOWER 70S.
&&
.SHORT TERM /TUESDAY NIGHT/...
LINGERING MOISTURE ASSOCIATED WITH AN EAST-WEST ORIENTED FRONT WILL
CONTINUE TO AFFECT THE REGION. THE MODELS KEEP BROAD UPPER-LEVEL
TROUGH WITH A SERIES OF SHORTWAVES MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. THIS WILL CONTINUE THE CHANCE FOR SHOWER AND
THUNDERSTORM DEVELOPMENT TUESDAY AND TUESDAY NIGHT AND INTO
WEDNESDAY. KEPT TEMPERATURES BELOW GUIDANCE WITH THE EXPECTED RAIN
AND CLOUDINESS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
SURFACE HIGH PRESSURE BEGINS TO BUILD DOWN INTO THE CAROLINAS ON
THURSDAY AND THE CHANCE OF SHOWERS AND THUNDERSTORMS LESSENS INTO
THE WEEKEND BUT THERE REMAINS ENOUGH MOISTURE FOR POSSIBLE AFTERNOON
SHOWERS AND THUNDERSTORMS. EXPECT HIGH TEMPERATURES NEAR OR A LITTLE
BELOW CLIMATOLOGY.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
MAIN FOCUS AT THIS TIME WILL BE THUNDERSTORM ACTIVITY IN THE NEAR
TERM. RAIN/THUNDERSTORMS AFFECTED ALL TERMINALS EARLIER TODAY.
CURRENT RADAR AT 2214Z INDICATES A BAND OF THUNDERSTORMS MOVING ENE
AWAY FROM CAE/CUB...WITH SOME ACTIVITY WELL WEST OF
AGS/DNL...MOVING EAST. AT THIS TIME..HANDLING THREAT WITH
VCTS APPEARS APPROPRIATE.
WILL EXPECT MOST CONVECTIVE ACTIVITY TO DISSIPATE BY LATE
EVENING/EARLY TONIGHT. CONCERN WILL THEN SHIFT TO ANY FOG/STRATUS
POTENTIAL. DESPITE ANY RAINFALL THAT MAY OCCUR AT TERMINALS...BUFKIT
INDICATES A SW 30 TO 35 KT LOW LEVEL JET TONIGHT...WHICH WOULD WORK
AGAINST FOG FORMATION. HOWEVER...AGS IS A VERY FOG PRONE LOCATION
AND AGS RECEIVED RAIN EARLIER TODAY. SO...SOME FOG POTENTIAL EXISTS
AT AGS. LATEST GUIDANCE ALSO INDICATING SOME STRATUS POTENTIAL.
AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED AFTERNOON/EVENING THUNDERSTORMS.
NOTE...AGS ASOS OUT OF SERVICE. NO OBSERVATIONS WILL BE AVAILABLE
THERE FROM 03Z-11Z. NO TAF AMENDMENTS WILL BE ISSUED FOR AGS DURING
THAT TIME.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 172034
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
434 PM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
4 PM UPDATE...THUNDERSTORMS MAINLY ORIENTED ALONG A SW-NE LINE
ACROSS THE PIEDMONT. CYCLONIC UPPER FLOW OVER THE REGION WILL
CONTINUE TO BE FAVORABLE FOR DEVELOPMENT THIS AFTN AND EVENING...BUT
GREATER FORCING SEEMS TO BE COMING FROM OUTFLOW BOUNDARIES. REVISED
POPS TO FOCUS IN THE VICINITY OF THE CURRENT STORMS AS A RESULT FOR
THE REST OF THE AFTN. SOME CU STILL DEVELOPING OVER THE CLEARER
AREAS OF THE MTNS AND WITH THE WEAK UPPER SUPPORT WILL MAINTAIN CHC
POPS THERE AS WELL. WRT TEMP TRENDS...TRIED TO ACCOUNT FOR THE
COOLING TSTM EFFECTS THOUGH THIS IS DIFFICULT TO DO PRECISELY.
THIS AFTERNOON THROUGH TONIGHT...THE OVERALL CONV COVERAGE IS
BEGINNING TO PICK UP ACROSS THE CWFA WITH A DEFINITE MINIMA SEEN
OVER THE UPSTATE AND FAR ERN ZONES. SOME CELLS HAVE BECOME FAIRLY
STRONG AND A COUPLE COULD REACH SEVERE CRITERIA...MAINLY FOR LARGE
HAIL...AS THE AFTERNOON PROGRESSES. THE UPPER LEVEL VORT ACTIVITY IS
RATHER WEAK AND ILL DEFINED OVER THE CWFA...BUT WILL COUNT ON
GENERAL EASTWARD DEVELOPMENT OF STORMS THROUGH THE EVENING. THINGS
WILL BEGIN TO WANE AFT SUNSET AND LOSS OF SBCAPE...HOWEVER UPPER
POCKETS OF PVA WILL TRAVERSE THE DEEPLY MOIST AIRMASS AND ISOL/SCT
-SHRA/TSTMS ARE NOT OUT OF THE QUESTION THROUGH DAYBREAK. MIN TEMPS
WILL BE HELD A COUPLE CATS OR SO ABOVE NORMAL IN THIS ENVIRONMENT.
A SHARPENING H5 S/W WILL MOVE INTO TN TOMORROW AND CREATE A GOOD
AMOUNT OF DYNAMIC OMEGA...ABOUT TWICE AS MUCH VV/S AS TODAY.
THUS...WILL ANTICIPATE GOOD COVERAGE OF SHOWERS AND STORMS EARLY
ON...ESP ACROSS THE NC MTNS WHERE CAT POPS ARE ADVERTISED AFT 15Z.
DEEP LAYERED SHEAR WILL BE ABOUT 10 KTS HIGHER TOMORROW...BUT SBCAPE
MAY ACTUALLY BE LOWER DUE TO ALL THE CLOUD COVER. YET...STILL THINK
A BETTER POTENTIAL EXISTS FOR SVR STORMS TOMORROW AFTERNOON AS THE
DEFINED S/W CROSSES OVERHEAD DURING MAX HEATING. MAX TEMPS WILL BE
SIMILAR TO TODAY/S...OR RIGHT AROUND NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AT 215 PM EDT MON...THERE IS GOOD MODEL CONSENSUS THAT A WEAK AREA
OF LOW PRESSURE AND ASSOCIATED WEAK COLD FRONT WILL CROSS THE AREA
FROM WEST TO EAST TUE NIGHT. HOWEVER...THERE ARE SOME MINOR TIMING
DIFFERENCES. THE 12Z GFS IS A LITTEL STRONGER WITH THE SURFACE LOW
AND FASTER WITH THE SYSTEMS MOVEMENT. THE 12Z NAM IS SIMILAR TO THE
SREF IN REGARD TO TIMING...SO HAVE LEANED MORE TOWARD A NAM
SOLUTION. HENCE...WE EXPECT NUMEROUS SHOWERS/THUNDERSTORMS TO AFFECT
THE WESTERN CAROLINAS AND NE GA TUE NIGHT. THE HIGHEST QPF AND POPS
SHOULD BE OVER NORTHERN SECTIONS CLOSER TO THE BEST UPPER FORCING.
WITH PWATS AROUND 2 INCHES...SOME LOCALLY HEAVY RAIN IS CERTAINLY A
POSSIBILITY. HOWEVER...DO NOT BELIEVE THAT THE FLOOD THREAT IS MORE
THAN ISOLATED AT THIS POINT.
ON WED...THE FRONT IS FORECAST TO MOVE EAST OF THE I-77 CORRIDOR
DURING THE MORNING. HENCE...WILL HAVE SCATTERED POPS IN THAT AREA
EARLY...BUT WILL TAKE THE MENTION OF PRECIP OUT OF THE FORECAST BY
MIDDAY. ON WED AFTERNOON...THE GFS AND THE CMC BRING WINDS
AROUND TO AN UPSLOPE COMPONENT OVER THE MOUNTAINS AND RESPOND WITH
SOME QPF THERE. THE NAM IS ESSENTIALLY DRY. WILL COMPROMISE AT THIS
POINT WITH JUST SOME VERY LOW END POPS OVER THE MOUNTAINS.
WITH CONTINUING LIGHT UPSLOPE FLOW ADVERTISED BY THE GLOBAL MODELS
WED NIGHT...CAN`T RULE OUT AT LEAST SOME WIDELY SCATTERED SHOWERS
CONTINUING OVER THE MOUNTAINS. ON THU...EXPECT THAT SCATTERED SHOWERS
AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS DURING THE
AFTERNOON AS THE WEAK UPSLOPE FLOW CONTINUES ALONG WITH WEAKLY
DIVERGENT FLOW ALOFT. USED THE ALL-BLEND GUIDANCE WHICH KEEPS MAX
TEMPS A CATEGORY OR SO BELOW AVERAGE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 110 PM EDT MONDAY...HEIGHTS WILL SLOWLY BUILD FROM THE WEST
FROM THURSDAY NIGHT INTO THE WEEKEND AS THE CENTER OF THE UPPER
RIDGE SHIFTS EAST FROM TEXAS TO SOMEWHERE OVER THE SE
STATES...DEPENDING ON WHICH MODEL YOU REFERENCE. A LIGHT EASTERLY
LOW LEVEL FLOW FRIDAY AND SATURDAY WILL SHIFT TO LIGHT SOUTHWEST BY
LATE SUNDAY INTO MONDAY. LIGHT WIND ALL THE WAY UP TO AROUND 500MB
WITH AROUND 10 KTS AT 500MB AND GENERALLY LESS DOWN TO THE SURFACE
FROM DAY 5 THROUGH NEW DAY 7. SURFACE HIGH PRESSURE CENTERED NEAR
NEW JERSEY THURSDAY NIGHT WILL RIDGE DOWN THROUGH THE CAROLINAS WITH
THE COOLER THAN NORMAL TEMPERATURES. THE CENTER OF THIS HIGH WILL
DRIFT TO NEAR BERMUDA LATE IN THE WEEKEND AND EARLY NEXT WEEK
PROVIDING A CHANGE IN AIRMASS COMBINED WITH INCREASING INFLUENCE OF
THE UPPER RIDGE BUILDING FROM THE WEST. CAPE VALUES ON FRIDAY AND
SATURDAY WILL BE A LITTLE HIGHER OVER THE MTNS...1000 TO 1600 ON THE
GFS FRIDAY. CAPE VALUES DROP OFF VERY LOW SUNDAY AND MONDAY. VARYING
LEVELS OF LOW LEVEL MOISTURE THROUGHOUT THE MEDIUM RANGE WILL SERVE
FOR THE PRODUCTION OF PM SHOWERS AND T-STORMS. TEMPERATURES A BIT
WARMER AT END OF THE WEEKEND AND START OF NEXT WEEK.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
AT KCLT /21Z UPDATE/...OUTFLOW BOUNDARY ARRIVAL IMMINENT FROM THE
NORTH AND WILL LIKELY KEEP WINDS GUSTY NW THRU 21-22Z. SLY WINDS
ABOVE THE OUTFLOW WILL CAUSE LLWS CONCERNS BRIEFLY DURING THAT
TIMEFRAME. TS CHANCES WILL REMAIN WORTHY OF A TEMPO THRU 23Z WITH
EFFECTS IN MVFR RANGE PER RECENT OBS AT OTHER TS-AFFECTED SITES.
MOISTURE REMAINS HIGH OVERNIGHT...BUT NOT ENOUGH TO MENTION PRECIP
OR CONVECTION AT THAT TIME. WITH STAGNANT AIRMASS IN PLACE...WILL
EXPECT A COUPLE HRS OF MVFR CIGS/VSBY AROUND DAYBREAK WITH LIFTING
CONDS AFT 13Z/14Z.
ELSEWHERE...THE BETTER CONV ACTIVITY WILL BE ACROSS THE NC AREAS
THIS AFTERNOON WHERE POCKETS OF DPVA CROSS A DEEPLY MOIST ATMOS. A
LINE OF CONV SHOULD REACH KHKY IN THE NEXT HOUR OR SO...SO
PREDOMINATE TSTMS ARE GIVEN FOR THE FIRST FEW HRS. THERE ISNT ENOUGH
CONFIDENCE TO ADD ANYTHING BUT A TEMPO TSTM OR VCTS...ESP OUTSIDE
THE HIGHER TERRAIN THROUGH 00Z/01Z. KEPT DIURNAL VCSH ACROSS THE NC
TAF SITES WITH INCREASING LIFT. ALL SITES SHOULD SEE EITHER A VSBY
OR CIG MFVR RESTRICTION AROUND DAYBREAK...WITH KAVL LIKELY SEEING
IFR VSBY AFT 10Z FOR A FEW HRS.
OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 97% HIGH 82% HIGH 98%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 89% HIGH 81% HIGH 98%
KHKY HIGH 100% HIGH 100% MED 77% HIGH 98%
KGMU HIGH 100% HIGH 100% HIGH 95% HIGH 100%
KAND HIGH 100% HIGH 93% HIGH 85% HIGH 88%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...DEO
AVIATION...SBK/WIMBERLEY
000
FXUS62 KCHS 172008
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
408 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF MID AFTERNOON...SHOWERS AND THUNDERSTORMS ARE EXPANDING IN
COVERAGE...MOSTLY INLAND...BUT ALSO CLOSER TO THE COAST ALONG THE
SEA BREEZE. EXPECT DECENT COVERAGE OF CONVECTION THROUGH THIS
EVENING DUE TO DEEP MOISTURE...SHORTWAVE ENERGY ALOFT...AND
SEVERAL BOUNDARIES SUCH AS THE SEA BREEZE AND CONVECTIVE OUTFLOWS.
COVERAGE SHOULD WANE TOWARD MIDNIGHT AS INSTABILITY
DIMINISHES...LIKELY TRANSITIONING OVER THE COASTAL WATERS WITH THE
BETTER INSTABILITY. THERE COULD BE A FEW SEVERE STORMS WITH
DAMAGING WINDS AND/OR LARGE HAIL THROUGH EARLY EVENING...MAINLY
WHERE BOUNDARY COLLISIONS OCCUR. IT WILL BE MILD WITH LOWS CLOSE
TO 70 INLAND RANGING TO THE MID 70S ALONG THE COAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...SFC HIGH PRESSURE WILL GRADUALLY BREAK DOWN EARLY AS A SFC
LOW TRACKS OVER THE TENNESSEE VALLEY AND TO THE MID ATLANTIC STATES.
SOUTHWEST FLOW AHEAD OF THE SFC LOW WILL LIKELY CONTRIBUTE TO
INCREASING LOW LVL MOISTURE OVER THE SOUTHEAST WHILE A SERIES OF H5
SHORTWAVES BEGIN TO SWING AROUND THE SOUTHERN PERIPHERY OF A BROAD
MID LVL TROUGH CENTERED NORTHEAST OF THE GREAT LAKES. CHANCES OF
SHOWERS/THUNDERSTORMS SHOULD INCREASE IN COVERAGE DURING THE
AFTERNOON AS TEMPS WARM INTO THE MID/UPPER 80S...ESPECIALLY FOR
INLAND LOCATIONS. GIVEN SFC DEWPTS IN THE LOW 70S...PWATS NEAR 2.0
INCHES...AND WEAK MID/UPPER LVL FLOW...EXPECT PULSE TYPE
THUNDERSTORMS CAPABLE OF PRODUCING BRIEF WIND GUSTS AND HEAVY
RAINFALL. SHOWER/THUNDERSTORM ACTIVITY SHOULD CONTINUE THROUGH THE
OVERNIGHT PERIOD AS A SFC COLD FRONT APPROACHES FROM THE
WEST/NORTHWEST LATE. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE
LOW/MID 70S.
WEDNESDAY AND THURSDAY...A SFC COLD FRONT WILL SLOWLY SHIFT OVER
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WEDNESDAY MORNING
BEFORE GRADUALLY STALLING OVER OR JUST SOUTH OF THE REGION ON
THURSDAY. AS THIS OCCURS...PWATS NEAR 2.0 INCHES ALONG WITH MID LVL
FORCING SHOULD FAVOR A PERIOD OF SHOWERS/THUNDERSTORMS EARLY
WEDNESDAY WITH COLD FROPA BEFORE ACTIVITY SHIFTS SOUTH OVER GEORGIA
ZONES ON THURSDAY. SHOWERS/THUNDERSTORMS MAY PRODUCE HEAVY RAINFALL
GIVEN THE AMOUNT OF MOISTURE AND WEAK WINDS IN PLACE. GREATEST
COVERAGE OF ACTIVITY WILL LIKELY BE ALONG OR NEAR THE FRONT
WEDNESDAY MORNING...WITH A 40-60 PERCENT CHANCE OF PRECIPITATION. BY
THURSDAY...CHANCES OF PRECIP SHOULD BEGIN TO DECLINE OVER SC ZONES
WHILE THE FRONT STALLS AND WEAKENS SOUTH OF INTERSTATE 16 IN
GEORGIA. HAVE MAINTAINED 30-40 POPS OVER THE REGION THURSDAY WITH
HIGHEST CHANCES FOR SOUTHERN GA ZONES. OVERALL HIGH TEMPS ARE
EXPECTED TO PEAK IN THE MID/UPPER 80S OVER MOST LOCATIONS
WEDNESDAY...WITH SLIGHTLY COOLER TEMPS IN THE MID 80S OVER SOUTH
CAROLINA ON THURSDAY BEHIND THE FRONT. WEDNESDAY NIGHT LOWS ARE
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
GENERALLY VFR. RISK FOR SHOWERS/TSTMS WILL INCREASE THIS AFTERNOON
INTO EARLY EVENING AS DEEP MOISTURE MOVE INTO THE AREA IN
ASSOCIATION WITH UPPER-LEVEL SHORTWAVE ENERGY AND SEVERAL
LOW-LEVEL BOUNDARIES INCLUDING THE SEA BREEZE...DIFFERENTIAL
HEATING AND CONVECTIVE OUTFLOWS. MAINTAINED THE TEMPO GROUP FOR
TSRA AT KCHS AS SHRA ARE ALREADY DEVELOPING IN THE VICINITY.
AMENDMENTS WILL MOST CERTAINLY BE NEEDED THROUGHOUT THE REST OF
THE AFTERNOON...ESPECIALLY AT KSAV...AS MESOSCALE AND SHORT-TERM
RADAR TRENDS BECOME MORE APPARENT. THERE WILL BE AT LEAST A SMALL
RISK FOR SHRA/TSRA THE REST OF THE TAF PERIOD BEYOND THIS
EVENING...ESPECIALLY AT KCHS WHERE DEEPER MOISTURE IS
EXPECTED...BUT CONFIDENCE IS TOO LOW TO MENTION ATTM.
EXTENDED AVIATION...EXTENDED AVIATION...PERIODIC FLIGHT
RESTRICTIONS TUESDAY THROUGH THURSDAY IN ASSOCIATION WITH
SCATTERED TO NUMEROUS SHRA/TSRA...MAINLY DURING AFTERNOON HOURS.
&&
.MARINE...
TONIGHT...WINDS WILL INCREASE SLIGHTLY AHEAD OF AN APPROACHING
COLD FRONT. SPEEDS COULD REACH AS HIGH AS 15-20 KT AT TIMES WITH
SEAS 2-4 FT...HIGHEST E.
TUESDAY THROUGH FRIDAY...WINDS/SEAS WILL LIKELY REMAIN BELOW SMALL
CRAFT ADVISORY THRESHOLDS FOR MUCH OF THE DAY TUESDAY BEFORE
INCREASING TUESDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS BETWEEN
HIGH PRESSURE OVER THE WESTERN ATLANTIC AND A SFC COLD FRONT
APPROACHING THE WATERS FROM THE WEST/NORTHWEST LATE. AS A
RESULT...SOUTH/SOUTHWEST FLOW IS ANTICIPATED TO SURGE TUESDAY NIGHT
WITH 20-25 KT WINDS AND SEAS UP TO 5 FT BEYOND 20 NM. EXPECT WIND
DIRECTIONS TO VEER WEST/NORTHWEST AS THE FRONT STEADILY SLIPS OVER
THE WATERS WEDNESDAY INTO THURSDAY...WITH WIND SPEEDS DIMINISHING AS
THE FRONT WEAKENS/STALLS. NUMERICAL MODEL SOLUTIONS DIFFER REGARDING
THE PRECISE LOCATION OF THE STALLING FRONT...BUT WILL LEAN TOWARD
PERSISTENCE IN INDICATING A GENERAL EAST/NORTHEAST FLOW FOR THURSDAY
AND FRIDAY. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY
CONDITIONS THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...RJB
SHORT TERM...DPB/RJB
LONG TERM...WMS
AVIATION...DPB/RJB
MARINE...DPB/RJB
000
FXUS62 KCHS 171956
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
356 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL THEN BUILD FROM THE NORTH INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF MID AFTERNOON...SHOWERS AND THUNDERSTORMS ARE EXPANDING IN
COVERAGE...MOSTLY INLAND...BUT ALSO CLOSER TO THE COAST ALONG THE
SEA BREEZE. EXPECT DECENT COVERAGE OF CONVECTION THROUGH THIS
EVENING DUE TO DEEP MOISTURE...SHORTWAVE ENERGY ALOFT...AND
SEVERAL BOUNDARIES SUCH AS THE SEA BREEZE AND CONVECTIVE OUTFLOWS.
COVERAGE SHOULD WANE TOWARD MIDNIGHT AS INSTABILITY
DIMINISHES...LIKELY TRANSITIONING OVER THE COASTAL WATERS WITH THE
BETTER INSTABILITY. THERE COULD BE A FEW SEVERE STORMS WITH
DAMAGING WINDS AND/OR LARGE HAIL THROUGH EARLY EVENING...MAINLY
WHERE BOUNDARY COLLISIONS OCCUR. IT WILL BE MILD WITH LOWS CLOSE
TO 70 INLAND RANGING TO THE MID 70S ALONG THE COAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
MONDAY...AN IMMENSE MID AND UPPER LEVEL TROUGH WILL BE FOUND OVER SE
CANADA...WHILE A FLAT AND STRETCHED OUT RIDGE IS LOCATED FROM THE SW
ATLANTIC ACROSS THE GULF AND NORTHERN OLD MEXICO INTO THE SE
PACIFIC. THE LOCAL REGIME WILL LIE NEAR THE SOUTHERN EXTENSION OF A
SLIGHTLY CYCLONIC FLOW ALOFT...WITH WEAK ENTRENCHED SHORT WAVES
FOUND WITHIN THE SOUTHERN STREAM OF THE JET. ONE OF THESE FEATURES
WILL TRIGGER THE DEVELOPMENT OF A VERY WEAK WARM FRONT OR TROUGH
ACROSS SOUTHERN GA IN THE AFTERNOON...AS THE LAST OF THE BERMUDA
SURFACE HIGH STRIVES TO HANG ON. THE MOST NOTICEABLE CHANGES IN THE
AIR MASS WILL BE THE RETURN OF HIGHER DEW POINTS...MUCH GREATER
MOISTURE AS PWATS TOP OUT NEAR 1.8 TO 1.9 INCHES AND WARMER TEMPS.
ALL THIS IS COURTESY OF THE RETURN FLOW AROUND THE ATLANTIC RIDGE.
INSTABILITY AND ESPECIALLY CAPE WILL BE AT HIGHER VALUES...THE
PERSISTENT SUBSIDENCE CAP WILL HAVE ERODED WHILE CINH WANES
THROUGHOUT THE DAY...AND THERE IS A LITTLE COOLER CONDITIONS IN THE
MID LEVELS. THE COMBINED INFLUENCES WILL ALLOW FOR THE RESUMPTION OF
OUR TYPICAL WARM SEASON CONVECTION...TRIGGERED BY THE SEA
BREEZE...THE SOUTHERN GA TOUGH OR WARM FRONT AND UPSTREAM BOUNDARIES
THAT COULD DRIFT IN WITH THE WESTERLY FLOW. DUE TO A SLOW STORM
MOTION OF NO MORE THAN ABOUT 10 KT AND THE ELEVATED PWATS...LOCALLY
HEAVY RAINS CAN OCCUR IN SOME OF THE MORE PERSISTENT STORMS.
CONVECTION WILL HOLD OFF UNTIL LATE MORNING OR EARLY AFTERNOON WHEN
WE REACH OUR TRIGGER TEMPS...WITH HIGHEST AFTERNOON COVERAGE MAINLY
IN THE SCATTERED RANGE...FROM 30 POPS NEAR THE COAST TO 50 POPS FAR
INLAND. DESPITE PARTLY TO MOSTLY CLOUDY SKY CONDITIONS...WARM
ADVECTION AND A STRETCHING OF THE LOW LEVEL THICKNESS WILL GENERATE
MAX TEMPS WITHIN A DEGREE OR TWO EITHER SIDE OF 90 INLAND FROM THE
INTRA-COASTAL WATERS.
MONDAY NIGHT...ALTHOUGH THERE IS A RETURN TO THE CINH AS PER
SOUNDINGS...GIVEN THAT THE SURF ACE TROUGH OR WARM FRONT WILL LIFT
THROUGH THE FORECAST AREA AND THERE IS SOME SHORT WAVE ENERGY
ALOFT...WE FEEL THAT SLIGHT CHANCE AND CHANCE POPS ARE JUSTIFIED
DESPITE THE NOCTURNAL ENVIRONMENT. OUR GRIDS WILL SHOW THE GREATEST
POPS ALONG THE NW RANGE OF THE CWFA DURING THE EVENING...THEN
TRANSITIONING TO OVER THE CHARLESTON TRI-COUNTY ZONES LATE AT NIGHT
IN PROXIMITY TO THE SURFACE FEATURE. MINIMUM TEMPS WILL BE NEAR OR
SLIGHTLY ABOVE NORMAL.
TUESDAY THROUGH WEDNESDAY...THE LARGE SCALE PATTERN ACROSS THE NORTH
AMERICAN CONTINENT WILL BE HIGHLY AMPLIFIED AND SOMEWHAT PROGRESSIVE
THROUGH THE PERIOD. LOCALLY WE WILL LIE NEAR THE SOUTHERN REACHES OF
CYCLONIC FLOW OVER THE EASTERN UNITED STATES...WITH PERIODIC MID
LEVEL PERTURBATIONS TO PASS ON THROUGH. SIMULTANEOUSLY AT THE
SURFACE WE WILL FIND A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE
VALLEY ON TUESDAY THAT STRUGGLES TO PUSH SE THROUGH WEDNESDAY. THE
FRONT BECOMES ORIENTED MORE PARALLEL TO THE FLOW ALOFT...WHILE AT
THE SAME TIME WAVES OF LOW PRESSURE PREVENT THE FRONT FROM SHIFTING
SOUTH AND SE AT MORE THAN A CRAWL. PRESENTLY IT LOOKS LIKE WE WILL
REMAIN IN THE WARM SECTOR SOUTH OF THE FRONT THROUGH THE MIDDLE OF
THE WEEK...AWAITING THE FORMATION OF ONE LAST WAVE THAT CLOSES INTO
A LOW OFF THE NC COAST LATE WEDNESDAY OR WEDNESDAY NIGHT. THERE IS
AMPLE INSTABILITY AND MOISTURE TO PRODUCE AT LEAST SCATTERED
CONVECTION. THERMODYNAMICS ARE NOT OVERLY IMPRESSIVE IN REGARDS TO
SEVERE WEATHER...BUT AT THIS TIME OF YEAR THERE IS ALWAYS AT
LEAST AN ISOLATED RISK SHOULD ANY BOUNDARY INTERACTIONS RESULT IN
STRONGER UPDRAFTS. COMPRESSIONAL HEATING IN ADVANCE OF THE COLD
FRONT FRONT...AIDED BY A DEEP WESTERLY FLOW OFF THE APPALACHIANS
WILL ALLOW FOR MANY LOCATIONS TO PEAK AT OR ABOVE 90 EACH AFTERNOON.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
GENERALLY VFR. RISK FOR SHOWERS/TSTMS WILL INCREASE THIS AFTERNOON
INTO EARLY EVENING AS DEEP MOISTURE MOVE INTO THE AREA IN
ASSOCIATION WITH UPPER-LEVEL SHORTWAVE ENERGY AND SEVERAL
LOW-LEVEL BOUNDARIES INCLUDING THE SEA BREEZE...DIFFERENTIAL
HEATING AND CONVECTIVE OUTFLOWS. MAINTAINED THE TEMPO GROUP FOR
TSRA AT KCHS AS SHRA ARE ALREADY DEVELOPING IN THE VICINITY.
AMENDMENTS WILL MOST CERTAINLY BE NEEDED THROUGHOUT THE REST OF
THE AFTERNOON...ESPECIALLY AT KSAV...AS MESOSCALE AND SHORT-TERM
RADAR TRENDS BECOME MORE APPARENT. THERE WILL BE AT LEAST A SMALL
RISK FOR SHRA/TSRA THE REST OF THE TAF PERIOD BEYOND THIS
EVENING...ESPECIALLY AT KCHS WHERE DEEPER MOISTURE IS
EXPECTED...BUT CONFIDENCE IS TOO LOW TO MENTION ATTM.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS POSSIBLE LATER
MONDAY THROUGH THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA.
&&
.MARINE...
TONIGHT...WINDS WILL INCREASE SLIGHTLY AHEAD OF AN APPROACHING
COLD FRONT. SPEEDS COULD REACH AS HIGH AS 15-20 KT AT TIMES WITH
SEAS 2-4 FT...HIGHEST E.
MONDAY AND MONDAY NIGHT...THE LOCAL DOMAIN WILL BE PLACED WITHIN THE
WEST AND NW PORTION OF THE SUB-TROPICAL ATLANTIC RIDGE MONDAY THAT
GRADUALLY GIVES WAY TO A WEAK WARM FRONT OR SURFACE TROUGH THAT
PROGRESSES THROUGH MONDAY NIGHT. WHILE THERE WILL BE SOME INCREASE
IN WINDS WITH THE SEA BREEZE CIRCULATION MONDAY AFTERNOON AND WITH
NOCTURNAL LOW LEVEL JETTING MONDAY NIGHT...SOUTH AND SW WINDS WILL
GENERALLY HOLD UNDER 15-17 KT. SEAS AROUND 2-3 FEET MONDAY WILL RISE
ABOUT ANOTHER FOOT MONDAY NIGHT. ISOLATED TO SCATTERED CONVECTION
WILL FINALLY MAKE A RETURN TO THE COASTAL WATERS DURING THIS TIME.
TUESDAY THROUGH WEDNESDAY...THE QUASI-WARM FRONT OR SURFACE TROUGH
WILL LIFT NORTH OF THE MARINE COMMUNITY EARLY IN THE PERIOD...WHILE
WE FIND THE ATLANTIC RIDGE SUBDUED TO THE SOUTH. MEANWHILE...AN
UPSTREAM COLD FRONT WILL RELUCTANTLY MAKE A SE PUSH TOWARD THE
WATERS TUESDAY NIGHT AND WEDNESDAY. STILL TOO MUCH UNCERTAINTY AS TO
HOW FAR THE FRONT WILL BE ABLE TO PENETRATE...AS THE OCEANIC RIDGE
TO THE SOUTH AND SE ATTEMPTS TO HOLD FIRM. WE DO FEEL CONFIDENT THAT
WINDS AND SEAS WILL ASCEND TUESDAY AND TUESDAY NIGHT...WITH A
TIGHTENING OF THE PRESSURE GRADIENT BETWEEN THE UPSTREAM COLD FRONT
AND THE ATLANTIC HIGH. EVEN SO...ODDS AT THIS STAGE ARE AGAINST ANY
SMALL CRAFT ADVISORY CONDITIONS. WIND AND SEA CONDITIONS WILL THEN
BE DETERMINED BY WHERE THE FRONT ALIGNS ITSELF ON WEDNESDAY...BUT NO
MATTER WHERE IT IS LOCATED...ADVISORY HEADLINES ARE NOT ANTICIPATED.
MARINERS ARE ADVISED THAT AT LEAST SCATTERED CONVECTION WILL
OCCUR...AND WE/LL MAINTAIN A WEATHER WATCH FOR THE POSSIBLE
ORGANIZATION OF STRONGER STORMS MOVING OFF THE COAST IN ADVANCE OF
THE COLD FRONT.
THURSDAY THROUGH FRIDAY...THE FRONT LOOKS TO BECOME MORE DIFFUSE
NEAR OR JUST SE OF THE LOCAL WATERS...AS HIGH PRESSURE BUILDS OVER
NEW ENGLAND AND THE MID ATLANTIC REGION. WINDS AND SEAS WILL BE WELL
BELOW ANY CRITERIA FOR SMALL CRAFT ADVISORIES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...RJB
SHORT TERM...DPB
LONG TERM...WMS
AVIATION...RJB/DPB
MARINE...RJB/DPB
000
FXUS62 KGSP 171848
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
248 PM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
THIS AFTERNOON THROUGH TONIGHT...THE OVERALL CONV COVERAGE IS
BEGINNING TO PICK UP ACROSS THE CWFA WITH A DEFINITE MINIMA SEEN OVER
THE UPSTATE AND FAR ERN ZONES. SOME CELLS HAVE BECOME FAIRLY STRONG
AND A COUPLE COULD REACH SEVERE CRITERIA...MAINLY FOR LARGE
HAIL...AS THE AFTERNOON PROGRESSES. THE UPPER LEVEL VORT ACTIVITY IS
RATHER WEAK AND ILL DEFINED OVER THE CWFA...BUT WILL COUNT ON
GENERAL EASTWARD DEVELOPMENT OF STORMS THROUGH THE EVENING. THINGS
WILL BEGIN TO WANE AFT SUNSET AND LOSS OF SBCAPE...HOWEVER UPPER
POCKETS OF PVA WILL TRAVERSE THE DEEPLY MOIST AIRMASS AND ISOL/SCT
-SHRA/TSTMS ARE NOT OUT OF THE QUESTION THROUGH DAYBREAK. MIN TEMPS
WILL BE HELD A COUPLE CATS OR SO ABOVE NORMAL IN THIS ENVIRONMENT.
A SHARPENING H5 S/W WILL MOVE INTO TN TOMORROW AND CREATE A GOOD
AMOUNT OF DYNAMIC OMEGA...ABOUT TWICE AS MUCH VV/S AS TODAY.
THUS...WILL ANTICIPATE GOOD COVERAGE OF SHOWERS AND STORMS EARLY
ON...ESP ACROSS THE NC MTNS WHERE CAT POPS ARE ADVERTISED AFT 15Z.
DEEP LAYERED SHEAR WILL BE ABOUT 10 KTS HIGHER TOMORROW...BUT SBCAPE
MAY ACTUALLY BE LOWER DUE TO ALL THE CLOUD COVER. YET...STILL THINK
A BETTER POTENTIAL EXISTS FOR SVR STORMS TOMORROW AFTERNOON AS THE
DEFINED S/W CROSSES OVERHEAD DURING MAX HEATING. MAX TEMPS WILL BE
SIMILAR TO TODAY/S...OR RIGHT AROUND NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AT 215 PM EDT MON...THERE IS GOOD MODEL CONSENSUS THAT A WEAK AREA
OF LOW PRESSURE AND ASSOCIATED WEAK COLD FRONT WILL CROSS THE AREA
FROM WEST TO EAST TUE NIGHT. HOWEVER...THERE ARE SOME MINOR TIMING
DIFFERENCES. THE 12Z GFS IS A LITTEL STRONGER WITH THE SURFACE LOW
AND FASTER WITH THE SYSTEMS MOVEMENT. THE 12Z NAM IS SIMILAR TO THE
SREF IN REGARD TO TIMING...SO HAVE LEANED MORE TOWARD A NAM
SOLUTION. HENCE...WE EXPECT NUMEROUS SHOWERS/THUNDERSTORMS TO AFFECT
THE WESTERN CAROLINAS AND NE GA TUE NIGHT. THE HIGHEST QPF AND POPS
SHOULD BE OVER NORTHERN SECTIONS CLOSER TO THE BEST UPPER FORCING.
WITH PWATS AROUND 2 INCHES...SOME LOCALLY HEAVY RAIN IS CERTAINLY A
POSSIBILITY. HOWEVER...DO NOT BELIEVE THAT THE FLOOD THREAT IS MORE
THAN ISOLATED AT THIS POINT.
ON WED...THE FRONT IS FORECAST TO MOVE EAST OF THE I-77 CORRIDOR
DURING THE MORNING. HENCE...WILL HAVE SCATTERED POPS IN THAT AREA
EARLY...BUT WILL TAKE THE MENTION OF PRECIP OUT OF THE FORECAST BY
MIDDAY. ON WED AFTERNOON...THE GFS AND THE CMC BRING WINDS
AROUND TO AN UPSLOPE COMPONENT OVER THE MOUNTAINS AND RESPOND WITH
SOME QPF THERE. THE NAM IS ESSENTIALLY DRY. WILL COMPROMISE AT THIS
POINT WITH JUST SOME VERY LOW END POPS OVER THE MOUNTAINS.
WITH CONTINUING LIGHT UPSLOPE ADVERTISED BY THE GLOBAL MODELS WED
NIGHT...CAN`T RULE OUT AT LEAST SOME WIDELY SCATTERED SHOWERS
CONTINUING OVER THE MOUNTAINS. ON THU...EXPECT THAT SCATTERD SHOWERS
AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS DURING THE
AFTERNOON AS THE WEAK UPSLOPE FLOW CONTINUES ALONG WITH WEAKLY
DIVERGENCT FLOW ALOFT. USED THE ALL-BLEND GUIDANCE WHICH KEEPS MAX
TEMPS A CATEGORY OR SO BELOW AVERAGE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 110 PM EDT MONDAY...HEIGHTS WILL SLOWLY BUILD FROM THE WEST
FROM THURSDAY NIGHT INTO THE WEEKEND AS THE CENTER OF THE UPPER
RIDGE SHIFTS EAST FROM TEXAS TO SOMEWHERE OVER THE SE
STATES...DEPENDING ON WHICH MODEL YOU REFERENCE. A LIGHT EASTERLY
LOW LEVEL FLOW FRIDAY AND SATURDAY WILL SHIFT TO LIGHT SOUTHWEST BY
LATE SUNDAY INTO MONDAY. LIGHT WIND ALL THE WAY UP TO AROUND 500MB
WITH AROUND 10 KTS AT 500MB AND GENERALLY LESS DOWN TO THE SURFACE
FROM DAY 5 THROUGH NEW DAY 7. SURFACE HIGH PRESSURE CENTERED NEAR
NEW JERSEY THURSDAY NIGHT WILL RIDGE DOWN THROUGH THE CAROLINAS WITH
THE COOLER THAN NORMAL TEMPERATURES. THE CENTER OF THIS HIGH WILL
DRIFT TO NEAR BERMUDA LATE IN THE WEEKEND AND EARLY NEXT WEEK
PROVIDING A CHANGE IN AIRMASS COMBINED WITH INCREASING INFLUENCE OF
THE UPPER RIDGE BUILDING FROM THE WEST. CAPE VALUES ON FRIDAY AND
SATURDAY WILL BE A LITTLE HIGHER OVER THE MTNS...1000 TO 1600 ON THE
GFS FRIDAY. CAPE VALUES DROP OFF VERY LOW SUNDAY AND MONDAY. VARYING
LEVELS OF LOW LEVEL MOISTURE THROUGHOUT THE MEDIUM RANGE WILL SERVE
FOR THE PRODUCTION OF PM SHOWERS AND T-STORMS. TEMPERATURES A BIT
WARMER AT END OF THE WEEKEND AND START OF NEXT WEEK.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AT KCLT...TIMING OF CONVECTION WILL BE TRICKY THIS AFTERNOON AS
UPPER S/W PATTERN IS WEAKLY DEFINED AND NO GOOD AREAS OF LLVL CONVG
EXIST. NONETHELESS...WILL COUNT OF INCREASING COVERAGE SHRA/TSTM
ACROSS THE PIEDMONT AFT 19Z AND DEEPER CELLULAR ACTIVITY WITHIN THE
TAF ZONE AND POSSIBLY PREDOMINATE FOR A COUPLE HRS THROUGH 23Z/00Z.
MOISTURE REMAINS HIGH OVERNIGHT...BUT NOT ENOUGH TO MENTION PRECIP
OR CONVECTION. WITH STAGNANT AIRMASS IN PLACE...WILL EXPECT A COUPLE
HRS OF MVFR CIGS/VSBY AROUND DAYBREAK WITH LIFTING CONDS AFT
13Z/14Z.
ELSEWHERE...THE BETTER CONV ACTIVITY WILL BE ACROSS THE NC AREAS
THIS AFTERNOON WHERE POCKETS OF DPVA CROSS A DEEPLY MOIST ATMOS. A
LINE OF CONV SHOULD REACH KHKY IN THE NEXT HOUR OR SO...SO
PREDOMINATE TSTMS ARE GIVEN FOR THE FIRST FEW HRS. THERE ISNT ENOUGH
CONFIDENCE TO ADD ANYTHING BUT A TEMPO TSTM OR VCTS...ESP OUTSIDE
THE HIGHER TERRAIN THROUGH 00Z/01Z. KEPT DIURNAL VCSH ACROSS THE NC
TAF SITES WITH INCREASING LIFT. ALL SITES SHOULD SEE EITHER A VSBY
OR CIG MFVR RESTRICTION AROUND DAYBREAK...WITH KAVL LIKELY SEEING
IFR VSBY AFT 10Z FOR A FEW HRS.
OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 86%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 95% HIGH 80% HIGH 96%
KHKY HIGH 100% HIGH 100% HIGH 95% HIGH 85%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 96%
KAND HIGH 100% HIGH 100% HIGH 87% HIGH 88%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK
SHORT TERM...LG
LONG TERM...DEO
AVIATION...SBK
000
FXUS62 KCAE 171815
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
214 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...A WEAK SHORT WAVE WILL MOVE EASTWARD THROUGH
THE REGION THIS AFTERNOON. THIS MAY HELP TO TRIGGER SOME CONVECTIVE
ACTIVITY BUT EXPECT MAINLY JUST SCATTERED. A WEAKLY SHEARED
ENVIRONMENT WITH JUST MARGINAL LIS -2/-3...TOTALS 44/45 AND CAPES
LESS THAN 1000 J/KG. SOME HEAVY RAIN POSSIBLE IN SHOWERS AND
THUNDERSTORMS WITH PWAT AROUND 1.90 INCHES. SIX HOUR QPF VALUES
AROUND 0.10 OF AN INCH OR LESS. SO NOT MUCH FLOODING POTENTIAL
EXPECTED. AND LATEST SATELLITE PCPN ESTIMATE KEEPS FLOODING
POTENTIAL TO THE NORTH AND WEST IN THE LATEST SPENES.
TONIGHT...MAINLY DIURNAL ACTIVITY BUT NAM BRINGS ANOTHER WEAK
IMPULSE TO THE REGION LATE TONIGHT AFTER MIDNIGHT. SO...PLAN ON
KEEPING AT LEAST SOME LOW CHANCE...SAY AROUND 30 PERCENT AFTER
MIDNIGHT. OTHERWISE...EXPECT LOW TEMPERATURES MAINLY IN THE
LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
LINGERING MOISTURE ASSOCIATED WITH AN EAST-WEST ORIENTED FRONT WILL
CONTINUE TO AFFECT THE REGION. THE MODELS KEEP BROAD UPPER-LEVEL
TROUGH WITH A SERIES OF SHORTWAVES MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. THIS WILL CONTINUE THE CHANCE FOR SHOWER AND
THUNDERSTORM DEVELOPMENT TUESDAY AND TUESDAY NIGHT AND INTO
WEDNESDAY. KEPT TEMPERATURES BELOW GUIDANCE WITH THE EXPECTED RAIN
AND CLOUDINESS.
&&
.LONG TERM /THURSDAY THRU MONDAY/...
SURFACE HIGH PRESSURE BEGINS TO BUILD DOWN INTO THE CAROLINAS ON
THURSDAY AND THE CHANCE OF SHOWERS AND THUNDERSTORMS LESSENS INTO
THE WEEKEND BUT THERE REMAINS ENOUGH MOISTURE FOR POSSIBLE AFTERNOON
SHOWERS AND THUNDERSTORMS. EXPECT HIGH TEMPERATURES NEAR OR A LITTLE
BELOW CLIMATOLOGY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
ONE SHORT WAVE MOVED EAST THIS MORNING BUT RUC13 BRINGS ANOTHER
WEAK SHORT OVER THE REGION LATE THIS AFTERNOON ON INTO THE EVENING
HOURS. THIS MAY HELP TO GENERATE MORE SHOWERS AND THUNDERSTORMS
BUT FOR TIME BEING WILL JUST MENTION THUNDERSTORMS IN THE VICINITY
22Z-02Z ALL TAF SITES. MAINLY VFR CONDITIONS THIS AFTERNOON AND
EVENING EXCEPT IF CONVECTIVE ACTIVITY DEVELOPS...MAY SEE BRIEF
IFR-MVFR CONDITIONS. OVERNIGHT...WITH PLENTY OF LOW LEVEL MOISTURE
AND LOW LEVEL WINDS BELOW 1 KFT SOUTHWEST 12-15 KNOTS...STRATUS
IS A POSSIBILITY. MVFR CIGS OCCURRED THIS MORNING AT AGS...DNL AND
OGB AND MVFR CIGS NEAR 2 KFT ARE EXPECTED AGAIN TUESDAY MORNING
AROUND 10Z-13Z TIME FRAME. AFTER 13Z...MAINLY VFR CONDITIONS JUST
LIKE TODAY BUT ANOTHER WEAK IMPULSE MOVES THROUGH TUESDAY AFTERNOON
JUST LIKE TODAY AND MORE SHOWERS AND THUNDERSTORMS ARE POSSIBLE.
HOWEVER...WILL NOT INCLUDE IN TAF SITES DUE TO UNCERTAINTY AS TO
TIMING AND LOCATION.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 171758
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
158 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...A WEAK SHORT WAVE WILL MOVE EASTWARD THROUGH
THE REGION THIS AFTERNOON. THIS MAY HELP TO TRIGGER SOME CONVECTIVE
ACTIVITY BUT EXPECT MAINLY JUST SCATTERED. A WEAKLY SHEARED
ENVIRONMENT WITH JUST MARGINAL LIS -2/-3...TOTALS 44/45 AND CAPES
LESS THAN 1000 J/KG. SOME HEAVY RAIN POSSIBLE IN SHOWERS AND
THUNDERSTORMS WITH PWAT AROUND 1.90 INCHES. SIX HOUR QPF VALUES
AROUND 0.10 OF AN INCH OR LESS. SO NOT MUCH FLOODING POTENTIAL
EXPECTED. AND LATEST SATELLITE PCPN ESTIMATE KEEPS FLOODING
POTENTIAL TO THE NORTH AND WEST IN THE LATEST SPENES.
TONIGHT...MAINLY DIURNAL ACTIVITY BUT NAM BRINGS ANOTHER WEAK
IMPULSE TO THE REGION LATE TONIGHT AFTER MIDNIGHT. SO...PLAN ON
KEEPING AT LEAST SOME LOW CHANCE...SAY AROUND 30 PERCENT AFTER
MIDNIGHT. OTHERWISE...EXPECT LOW TEMPERATURES MAINLY IN THE
LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
HIGH MOISTURE ASSOCIATED WITH THE DIFFUSE EAST-WEST ORIENTED FRONT
WILL CONTINUE. THE MODELS KEEP BROAD UPPER-LEVEL TROUGHING WITH A
SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS. LEANED
TOWARD THE HIGHER GUIDANCE POPS. THE COOLER HIGH TEMPERATURE
GUIDANCE APPEARS BETTER BECAUSE OF EXPECTED CLOUDINESS. THE LOW
TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY THE FRONT REMAINING NEAR THE FORECAST
AREA THROUGH THE MEDIUM-RANGE PERIOD. THERE HAS BEEN INCONSISTENCY
IN THE PLACEMENT OF DEEPER MOISTURE. THE GFS ENSEMBLE MEANS AND
OPERATIONAL GFS MOS SUPPORT CHANCE POPS THROUGH THE PERIOD.
EXPECT HIGH TEMPERATURES NEAR OR A LITTLE BELOW CLIMATOLOGY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
ONE SHORT WAVE MOVED EAST THIS MORNING BUT RUC13 BRINGS ANOTHER
WEAK SHORT OVER THE REGION LATE THIS AFTERNOON ON INTO THE EVENING
HOURS. THIS MAY HELP TO GENERATE MORE SHOWERS AND THUNDERSTORMS
BUT FOR TIME BEING WILL JUST MENTION THUNDERSTORMS IN THE VICINITY
22Z-02Z ALL TAF SITES. MAINLY VFR CONDITIONS THIS AFTERNOON AND
EVENING EXCEPT IF CONVECTIVE ACTIVITY DEVELOPS...MAY SEE BRIEF
IFR-MVFR CONDITIONS. OVERNIGHT...WITH PLENTY OF LOW LEVEL MOISTURE
AND LOW LEVEL WINDS BELOW 1 KFT SOUTHWEST 12-15 KNOTS...STRATUS
IS A POSSIBILITY. MVFR CIGS OCCURRED THIS MORNING AT AGS...DNL AND
OGB AND MVFR CIGS NEAR 2 KFT ARE EXPECTED AGAIN TUESDAY MORNING
AROUND 10Z-13Z TIME FRAME. AFTER 13Z...MAINLY VFR CONDITIONS JUST
LIKE TODAY BUT ANOTHER WEAK IMPULSE MOVES THROUGH TUESDAY AFTERNOON
JUST LIKE TODAY AND MORE SHOWERS AND THUNDERSTORMS ARE POSSIBLE.
HOWEVER...WILL NOT INCLUDE IN TAF SITES DUE TO UNCERTAINTY AS TO
TIMING AND LOCATION.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 171752
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
152 PM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
130 PM UPDATE...CONV ACTIVITY IS BEGINNING TO FILL IN ACROSS THE WRN
ZONES AND INTO THE NC FHILLS. THE CURRENT POPS HAVE THIS SCENARIO
WELL IN HAND AND WILL ANTICIPATE CONTINUED DEVELOPMENT TO THE EAST
THROUGH THE NEXT UPDATE...MAINLY ACROSS THE NC ZONES. SOME CELLS
ARE BECOMING RELATIVELY DEEP AND PRODUCING PEA HAIL. WITH WEAK UPPER
ENERGY AND MODEST SBCAPE...DONT EXPECT MUCH MORE THAN A FEW SPS/S
OVER THE NEXT COUPLE OF HRS. MAX TEMPS LOOK GOOD AND HR/LY TRENDS IN
THE OTHER SENSIBLE WX HAVE REQUIRED ONLY MINOR TWEAKS.
1030 AM UPDATE...MANY UPDATES NEEDED TO THE GRIDS DUE TO SERVICE
BACKUP THIS MORNING. THE MAIN ISSUE OVER THE NEXT COUPLE HRS WILL BE
THE DEVELOPMENT OF CONVECTION INTO THE WRN ZONES. THE 88D IS SHOWING
GOOD RESPONSE AND SOME DEEP CELLS TO THE H5 S/W AND IS FILLING ATTM
ACROSS THE NRN GA AND SE/RN TN. POPS HAVE BEEN ADJ UP WEST AND
LOWERED EAST AND SE WHERE SBCIN IS HOLDING STRONG. THE HIRES MODELS
INDICATE THE UPSTATE AND PIEDMONT WILL BE ONE OF THE LAST AREAS TO
SEE SHRA/TSTM DEVELOPMENT AND THIS MAKES SENSE AMOUNT OF DNVA TO
OVERCOME IN THESE AREAS. SKY AND TEMPS/TDS WERE ALSO ADJUSTED PER
THE ADVANCEMENT OF ACTIVITY IN FROM THE WEST. MAX TEMPS WERE BUMPED
UP A LITTLE EAST USING THE LLVL THICKNESS SCHEME WHERE LESS CLOUD
COVER EARLY SHOULD ENABLE BETTER OVERALL HEATING.
AS OF 430 AM EDT MONDAY...SCATTERED SHOWER ACTIVITY CONTINUES ACROSS
PORTIONS OF THE NORTH AND SOUTH CAROLINA PIEDMONTS. EXPECTING THIS
ACTIVITY TO CONTINUE MOVING EASTWARD THROUGHOUT THE MORNING.
ELSEWHERE...MORE SHOWERS WILL BE MOVING IN FROM THE WEST AND
INCREASING IN COVERAGE LATER IN THE MORNING. THEREFORE...UPDATED
NEAR TERM POPS TO REFLECT RECENT RADAR TRENDS AND ADJUSTED
TEMPERATURES ACCORDING TO RECENT OBSERVATIONS. OTHERWISE...NO OTHER
CHANGES WERE MADE.
PREVIOUS DISCUSSION...
AS OF 250 AM EDT MONDAY...CURRENT RADAR TRENDS INDICATE A LARGE
SHIELD OF STRATIFORM PRECIPITATION LOCATED ACROSS NORTHEAST GEORGIA
AND THE WESTERN UPSTATE REGION OF SOUTH CAROLINA. OTHERWISE...BROAD
CYCLONIC FLOW WILL PROMOTE CONTINUED SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE PERIOD. SHORT RANGE MODEL GUIDANCE INDICATES A
SERIES OF MID-UPPER LEVEL VORTICITY MAXIMA PASSING THROUGH THE
REGION OVER THE NEXT 18-24 HOURS. IN RESPONSE...A MILDLY UNSTABLE
AIRMASS AT THE SURFACE WILL PROVIDE ENOUGH LOW LEVEL LIFTING
POTENTIAL FOR SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT MONDAY
MORNING. SOUNDINGS INDICATE SBCAPE VALUES GENERALLY RANGING FROM
500-1000 J/KG WITH THE HIGHEST VALUES LYING ACROSS WESTERN NORTH
CAROLINA DUE TO CURRENT SHOWER ACTIVITY WORKING OVER THE ATMOSPHERE
ACROSS THE UPSTATE AND NORTHEAST GEORGIA. BY LATE MORNING TO EARLY
AFTERNOON...EXPECTING SKY COVER TO INCREASE AS THE COLUMN MOISTENS
THEREBY DECREASING SURFACE HEATING. WITH THAT...MOST IF NOT ALL
ISOLATED THUNDERSTORM DEVELOPMENT WILL CEASE LEADING TO MORE OF A
STRATIFORM PRECIPITATION REGIME WITH EMBEDDED CLUSTERS OF HEAVIER
RAINFALL. SHOWER ACTIVITY WILL DECREASE FROM NORTH TO SOUTH AS
UPPER LEVEL IMPULSES EXIT THE REGION ON MONDAY EVENING. THE
OVERNIGHT HOURS OF TUESDAY MORNING SHOULD REMAIN MOSTLY DRY AS MODEL
GUIDANCE INDICATES A LULL IN THE SHOWER ACTIVITY. TEMPERATURES
THROUGH THIS PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE NORMAL FOR LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AT 315 AM EDT MON...A CLIPPER WAVE MOVING SE THROUGH THE MIDWEST ON
TUE WILL SHARPEN UP AN ERN TROUGH AXIS OVER THE APPALACHIANS TUE
NIGHT THROUGH WED. THE NUMERICAL MODELS ALL FEATURE WEAK SFC WAVES
AHEAD OF THE UPPER CLIPPER MOVING EAST ALONG THE LINGERING WEAK
BOUNDARY IN PLACE OVER THE FORECAST AREA. IN ADDITION...THE
STRONGEST RIGHT ENTRANCE REGION UPPER JET DIVERGENCE WILL CROSS THE
FORECAST AREA MAINLY TUE NIGHT INTO WED. THESE VARIOUS FORCING
MECHANISMS WILL COINCIDE WITH A ZONE OF RELATIVELY DEEP MOISTURE
ORIENTED W TO E ACROSS THE AREA TUE THROUGH MUCH OF WED. THIS WILL
REQUIRE SOLID CHC TO LOW END LIKELY POPS THROUGHOUT. THERE IS VERY
LIMITED SHEAR IN THE MODEL PROFILES TUE THROUGH WED...AND SFC BASED
INSTABILITY MAY ALSO BE LIMITED DESPITE THE HIGH DEWPOINTS BECAUSE
OF CLOUD COVER. LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREAT.
WILL CONTINUE TO FEATURE A SMALLER THAN CLIMO DIURNAL RANGE OF WARM
MIN TEMPS AND COOLER THAN NORMAL MAX TEMPS TUE THROUGH WED NIGHT
GIVEN THE CLOUD COVER AND PRECIP CHANCES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 110 PM EDT MONDAY...HEIGHTS WILL SLOWLY BUILD FROM THE WEST
FROM THURSDAY NIGHT INTO THE WEEKEND AS THE CENTER OF THE UPPER
RIDGE SHIFTS EAST FROM TEXAS TO SOMEWHERE OVER THE SE
STATES...DEPENDING ON WHICH MODEL YOU REFERENCE. A LIGHT EASTERLY
LOW LEVEL FLOW FRIDAY AND SATURDAY WILL SHIFT TO LIGHT SOUTHWEST BY
LATE SUNDAY INTO MONDAY. LIGHT WIND ALL THE WAY UP TO AROUND 500MB
WITH AROUND 10 KTS AT 500MB AND GENERALLY LESS DOWN TO THE SURFACE
FROM DAY 5 THROUGH NEW DAY 7. SURFACE HIGH PRESSURE CENTERED NEAR
NEW JERSEY THURSDAY NIGHT WILL RIDGE DOWN THROUGH THE CAROLINAS WITH
THE COOLER THAN NORMAL TEMPERATURES. THE CENTER OF THIS HIGH WILL
DRIFT TO NEAR BERMUDA LATE IN THE WEEKEND AND EARLY NEXT WEEK
PROVIDING A CHANGE IN AIRMASS COMBINED WITH INCREASING INFLUENCE OF
THE UPPER RIDGE BUILDING FROM THE WEST. CAPE VALUES ON FRIDAY AND
SATURDAY WILL BE A LITTLE HIGHER OVER THE MTNS...1000 TO 1600 ON THE
GFS FRIDAY. CAPE VALUES DROP OFF VERY LOW SUNDAY AND MONDAY. VARYING
LEVELS OF LOW LEVEL MOISTURE THROUGHOUT THE MEDIUM RANGE WILL SERVE
FOR THE PRODUCTION OF PM SHOWERS AND T-STORMS. TEMPERATURES A BIT
WARMER AT END OF THE WEEKEND AND START OF NEXT WEEK.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AT KCLT...TIMING OF CONVECTION WILL BE TRICKY THIS AFTERNOON AS
UPPER S/W PATTERN IS WEAKLY DEFINED AND NO GOOD AREAS OF LLVL CONVG
EXIST. NONETHELESS...WILL COUNT OF INCREASING COVERAGE SHRA/TSTM
ACROSS THE PIEDMONT AFT 19Z AND DEEPER CELLULAR ACTIVITY WITHIN THE
TAF ZONE AND POSSIBLY PREDOMINATE FOR A COUPLE HRS THROUGH 23Z/00Z.
MOISTURE REMAINS HIGH OVERNIGHT...BUT NOT ENOUGH TO MENTION PRECIP
OR CONVECTION. WITH STAGNANT AIRMASS IN PLACE...WILL EXPECT A COUPLE
HRS OF MVFR CIGS/VSBY AROUND DAYBREAK WITH LIFTING CONDS AFT
13Z/14Z.
ELSEWHERE...THE BETTER CONV ACTIVITY WILL BE ACROSS THE NC AREAS
THIS AFTERNOON WHERE POCKETS OF DPVA CROSS A DEEPLY MOIST ATMOS. A
LINE OF CONV SHOULD REACH KHKY IN THE NEXT HOUR OR SO...SO
PREDOMINATE TSTMS ARE GIVEN FOR THE FIRST FEW HRS. THERE ISNT ENOUGH
CONFIDENCE TO ADD ANYTHING BUT A TEMPO TSTM OR VCTS...ESP OUTSIDE
THE HIGHER TERRAIN THROUGH 00Z/01Z. KEPT DIURNAL VCSH ACROSS THE NC
TAF SITES WITH INCREASING LIFT. ALL SITES SHOULD SEE EITHER A VSBY
OR CIG MFVR RESTRICTION AROUND DAYBREAK...WITH KAVL LIKELY SEEING
IFR VSBY AFT 10Z FOR A FEW HRS.
OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 86%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 95% HIGH 80% HIGH 96%
KHKY HIGH 100% HIGH 100% HIGH 95% HIGH 85%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 96%
KAND HIGH 100% HIGH 100% HIGH 87% HIGH 88%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG/SBK
SHORT TERM...HG
LONG TERM...HG
AVIATION...SBK
000
FXUS62 KCHS 171735
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
135 PM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL BUILD FROM THE NORTH INTO NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF EARLY AFTERNOON...ISOLATED SHOWERS INLAND WERE GAINING A BIT
MORE COVERAGE AND INTENSITY...ALTHOUGH NO LIGHTNING HAS BEEN
DETECTED YET. EXPECT COVERAGE OF SHOWERS TO CONTINUE TO INCREASE
ALONG WITH INSTABILITY WITH BOUNDARIES FROM THE SEA
BREEZE...DIFFERENTIAL HEATING AND CONVECTIVE OUTFLOWS HELPING TO
INCREASE/SUSTAIN NUMEROUS SHOWERS AND STORMS BY LATE AFTERNOON.
SOME STORMS COULD BECOME SEVERE WITH DAMAGING WINDS AND LARGE HAIL
BUT THE RELATIVELY WEAK DEEP SHEAR AND INCREASING DEEP MOISTURE
SHOULD PREVENT MUCH IN THE WAY OF SEVERE WEATHER. HEAVY RAINFALL
AND LOCALIZED FLOODING MAY BE THE BIGGER IMPACT. HIGHS LOOK TO BE
IN THE MID TO UPPER 80S AWAY FROM THE IMMEDIATE COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...SHOWER/TSTMS ACTIVITY WILL GRADUALLY WIND DOWN AS
INSTABILITY WANES WITH THE LOSS OF INSOLATION AND THE ATMOSPHERE
IS STEADILY OVERTURNED. THERE ARE SOME INDICATIONS THAT
CONVECTION COULD CLUSTER ALONG/NEAR THE ALTAMAHA RIVER EARLY THIS
EVENING AS THE GULF SEA BREEZE MAKES A RUN FOR THE FAR SOUTHERN
ZONES...BUT IT IS UNCLEAR WHETHER THE GULF SEA BREEZE WILL MAKE
IT THIS FAR NORTH. THIS WILL HAVE TO THE WATCHED CAREFULLY. WILL
CARRY 40-60 PERCENT POPS EARLY THIS EVENING...DIMINISHING TO 20-30
PERCENT FORTH OVERNIGHT HOURS. LOWS WILL RANGE FROM AROUND 70 WELL
INLAND TO THE MID 70S AT THE COAST.
TUESDAY...A PROGRESSIVE NEARLY ZONAL PATTERN ALOFT WILL ALLOW A
SERIES OF WEAK SHORTWAVES TO CONTINUALLY MOVE THROUGH THE SOUTHEAST
STATES EARLY IN THE WEEK. AT THE SURFACE...A WAVE OF LOW PRESSURE
WILL DEVELOP ALONG A COLD FRONT STRETCHING FROM APPROXIMATELY
UPSTATE SOUTH CAROLINA THROUGH COASTAL NORTH CAROLINA. THE
COMBINATION OF UPPER LEVEL ENERGY AND DEEP LAYER MOISTURE...ALONG
WITH FRONTAL CONVERGENCE...WILL SUPPORT INCREASING CONVECTIVE
COVERAGE BY TUESDAY AFTERNOON. THE BEST POTENTIAL FOR THUNDERSTORM
ACTIVITY WILL BE ALONG THE FAR INLAND TIER COUNTIES CLOSEST TO THE
LINGERING FRONT...YET SOLID DEEP WESTERLY FLOW SHOULD STILL PUSH
UPSTREAM CONVECTION TOWARD THE COAST. WILL THUS ADVERTISE
THUNDERSTORM CHANCES RANGING FROM 50 TO 60 PERCENT INLAND TO 40
PERCENT CLOSER TO THE COAST DURING THE DAYTIME HOURS. IF THE
CENTER OF THE MAIN SURFACE WAVE SLIPS TOWARD THE OUTER BANKS OF
NORTH CAROLINA LATE TUESDAY NIGHT...THEN SHOWER/THUNDERSTORM
COVERAGE WILL DECREASE FROM SOUTH TO NORTH AFTER MIDNIGHT.
SUFFICIENT SYNOPTIC SCALE FORCING WILL STILL MAINTAIN CHANCES IN
THE 20 PERCENT RANGE SOUTHEAST GEORGIA TO THE 30 TO 40 PERCENT
RANGE CHARLESTON TRI COUNTY REGION TOWARD THE PRE DAWN HOURS. HIGH
TEMPERATURES WILL REACH THE UPPER 80S TO AROUND 90 DEGREES AWAY
FROM THE LOCALLY COOLER COASTLINE.
WEDNESDAY...CONVECTIVE COVERAGE WILL SURGE AGAIN AFTER
DAYBREAK...AS THE AMPLIFYING SHORTWAVE TROUGH MOVING OVER THE EAST
COAST PULLS THE FRONT DIRECTLY INTO THE FORECAST AREA DURING THE
AFTERNOON HOURS. HAVE INDICATED HIGHEST THUNDERSTORM POTENTIAL OF
THE PERIOD ON WEDNESDAY...WITH LIKELY POPS FOR THE MAJORITY OF
THE ZONES AWAY FROM THE COASTLINE. THE AXIS OF THE LOW PRESSURE
WAVE WILL SHIFT INTO THE MARINE ZONES WITH THE MAIN SHORTWAVE
OVERNIGHT...PULLING DEEPEST MOISTURE AND ASSOCIATED CONVECTIVE
ACTIVITY TOWARD THE EASTERN HALF OF THE FORECAST AREA AND THE
COASTAL WATERS. HIGH TEMPERATURES ON WEDNESDAY WILL BE A BIT
TRICKY...ESPECIALLY ACROSS NORTHERN AREAS THAT COULD END UP ON THE
COOL SIDE OF THE DESCENDING FRONT. WILL INDICATE MID TO UPPER 80S
NORTHERN MOST ZONES AND UPPER 80S TO AROUND 90 FARTHER SOUTH.
THURSDAY...THE WEAK COLD FRONT WILL CONTINUE TO SLIP SOUTH THROUGH
THE FORECAST AREA EARLY IN THE DAY...BEFORE STALLING ALONG THE
SOUTHERN PERIPHERY AS IT BECOMES MORE PARALLEL TO FLOW ALOFT.
THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND ECMWF MODEL
SOLUTIONS REGARDING PRECIPITATION COVERAGE...A RESULT OF THE GFS
MAINTAINING A MORE PROMINENT UPPER TROUGH OVER THE SOUTHEAST
STATES. HAVE OPTED TO MAINTAIN SOLID THUNDERSTORM CHANCES ACROSS
THE AREA FOR THE AFTERNOON PERIOD...INDICATING SLIGHTLY HIGHER
POTENTIAL ACROSS THE SOUTHERN SECTIONS CLOSEST TO THE STALLED
BOUNDARY. HIGH TEMPERATURES COULD ONCE AGAIN REFLECT A SLIGHT
NORTHEAST/SOUTHWEST GRADIENT...WITH SUBTLE COOLER CONDITIONS IN
THE MID TO UPPER 80S CHARLESTON TRI COUNTY REGION COMPARED TO
AROUND 90 DEGREES FARTHER SOUTH NEAR THE ALTAMAHA RIVER.
OVERALL SEVERE POTENTIAL LOOKS LOW THROUGH THE PERIOD...AS THE
STRONGEST SYNOPTIC FORCING AND WIND FIELDS REMAIN NORTH OF THE
FORECAST AREA. HOWEVER...AS IS TYPICAL THIS TIME OF YEAR...AN
ISOLATED STRONG TO SEVERE THUNDERSTORM IS POSSIBLE WHERE BOUNDARY
INTERACTIONS OCCUR AND ENHANCE UPDRAFT STRENGTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
GENERALLY VFR. RISK FOR SHOWERS/TSTMS WILL INCREASE THIS AFTERNOON
INTO EARLY EVENING AS DEEP MOISTURE MOVE INTO THE AREA IN
ASSOCIATION WITH UPPER-LEVEL SHORTWAVE ENERGY AND SEVERAL
LOW-LEVEL BOUNDARIES INCLUDING THE SEA BREEZE...DIFFERENTIAL
HEATING AND CONVECTIVE OUTFLOWS. MAINTAINED THE TEMPO GROUP FOR
TSRA AT KCHS AS SHRA ARE ALREADY DEVELOPING IN THE VICINITY.
AMENDMENTS WILL MOST CERTAINLY BE NEEDED THROUGHOUT THE REST OF
THE AFTERNOON...ESPECIALLY AT KSAV...AS MESOSCALE AND SHORT-TERM
RADAR TRENDS BECOME MORE APPARENT. THERE WILL BE AT LEAST A SMALL
RISK FOR SHRA/TSRA THE REST OF THE TAF PERIOD BEYOND THIS
EVENING...ESPECIALLY AT KCHS WHERE DEEPER MOISTURE IS
EXPECTED...BUT CONFIDENCE IS TOO LOW TO MENTION ATTM.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS MONDAY NIGHT
THROUGH THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA.
&&
.MARINE...
TODAY...SOUTHERLY WIND REGIME WILL PERSIST WITH WINDS GENERALLY 10
KT OR LESS...POSSIBLY CLOSER TO 15 KT ALONG THE COAST WITH THE SEA
BREEZE...AND SEAS 2-4 FT...HIGHEST E.
TONIGHT...WINDS WILL INCREASE SLIGHTLY AHEAD OF AN APPROACHING
COLD FRONT. SPEEDS COULD REACH AS HIGH AS 15-20 KT AT TIMES WITH
SEAS 2-4 FT. SMALL CRAFT ADVISORY CONDITIONS ARE UNLIKELY AT THIS
TIME.
TUESDAY THROUGH FRIDAY...THE MARINE ZONES WILL BECOME SITUATED
BETWEEN AN APPROACHING COLD FRONT/SURFACE TROUGH INLAND AND
RETREATING HIGH PRESSURE TO THE EAST EARLY THIS WEEK. SOUTHERLY
FLOW WILL SURGE SLIGHTLY BY WEDNESDAY AS THE PRESSURE GRADIENT
TIGHTENS BETWEEN THE TWO FEATURES...SUPPORTING A BRIEF PERIOD OF
15 TO 20 KT WINDS AND SEAS UP TO 5 FT BEYOND 20 NM. EXPECT WIND
DIRECTIONS TO VEER WEST/NORTHWEST AS THE FRONT STEADILY SLIPS INTO
THE FORECAST AREA THURSDAY...AS SPEEDS DIMINISH A BIT WITHIN A
WEAKENING PRESSURE GRADIENT. NUMERICAL MODEL SOLUTIONS DIFFER
REGARDING THE PRECISE LOCATION OF THE STALLING FRONT BY LATE
WEEK...AND WILL LEAN TOWARD PERSISTENCE IN INDICATING A GENERAL
EAST/NORTHEAST FLOW FOR THURSDAY AND FRIDAY. WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY CONDITIONS THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...RJB
SHORT TERM...ST/WMS
LONG TERM...WMS
AVIATION...RJB/WMS
MARINE...ST/WMS
000
FXUS62 KGSP 171458
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1058 AM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE...MANY UPDATES NEEDED TO THE GRIDS DUE TO SERVICE
BACKUP THIS MORNING. THE MAIN ISSUE OVER THE NEXT COUPLE HRS WILL BE
THE DEVELOPMENT OF CONVECTION INTO THE WRN ZONES. THE 88D IS SHOWING
GOOD RESPONSE AND SOME DEEP CELLS TO THE H5 S/W AND IS FILLING ATTM
ACROSS THE NRN GA AND SE/RN TN. POPS HAVE BEEN ADJ UP WEST AND
LOWERED EAST AND SE WHERE SBCIN IS HOLDING STRONG. THE HIRES MODELS
INDICATE THE UPSTATE AND PIEDMONT WILL BE ONE OF THE LAST AREAS TO
SEE SHRA/TSTM DEVELOPMENT AND THIS MAKES SENSE AMOUNT OF DNVA TO
OVERCOME IN THESE AREAS. SKY AND TEMPS/TDS WERE ALSO ADJUSTED PER
THE ADVANCEMENT OF ACTIVITY IN FROM THE WEST. MAX TEMPS WERE BUMPED
UP A LITTLE EAST USING THE LLVL THICKNESS SCHEME WHERE LESS CLOUD
COVER EARLY SHOULD ENABLE BETTER OVERALL HEATING.
AS OF 430 AM EDT MONDAY...SCATTERED SHOWER ACTIVITY CONTINUES ACROSS
PORTIONS OF THE NORTH AND SOUTH CAROLINA PIEDMONTS. EXPECTING THIS
ACTIVITY TO CONTINUE MOVING EASTWARD THROUGHOUT THE MORNING.
ELSEWHERE...MORE SHOWERS WILL BE MOVING IN FROM THE WEST AND
INCREASING IN COVERAGE LATER IN THE MORNING. THEREFORE...UPDATED
NEAR TERM POPS TO REFLECT RECENT RADAR TRENDS AND ADJUSTED
TEMPERATURES ACCORDING TO RECENT OBSERVATIONS. OTHERWISE...NO OTHER
CHANGES WERE MADE.
PREVIOUS DISCUSSION...
AS OF 250 AM EDT MONDAY...CURRENT RADAR TRENDS INDICATE A LARGE
SHIELD OF STRATIFORM PRECIPITATION LOCATED ACROSS NORTHEAST GEORGIA
AND THE WESTERN UPSTATE REGION OF SOUTH CAROLINA. OTHERWISE...BROAD
CYCLONIC FLOW WILL PROMOTE CONTINUED SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE PERIOD. SHORT RANGE MODEL GUIDANCE INDICATES A
SERIES OF MID-UPPER LEVEL VORTICITY MAXIMA PASSING THROUGH THE
REGION OVER THE NEXT 18-24 HOURS. IN RESPONSE...A MILDLY UNSTABLE
AIRMASS AT THE SURFACE WILL PROVIDE ENOUGH LOW LEVEL LIFTING
POTENTIAL FOR SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT MONDAY
MORNING. SOUNDINGS INDICATE SBCAPE VALUES GENERALLY RANGING FROM
500-1000 J/KG WITH THE HIGHEST VALUES LYING ACROSS WESTERN NORTH
CAROLINA DUE TO CURRENT SHOWER ACTIVITY WORKING OVER THE ATMOSPHERE
ACROSS THE UPSTATE AND NORTHEAST GEORGIA. BY LATE MORNING TO EARLY
AFTERNOON...EXPECTING SKY COVER TO INCREASE AS THE COLUMN MOISTENS
THEREBY DECREASING SURFACE HEATING. WITH THAT...MOST IF NOT ALL
ISOLATED THUNDERSTORM DEVELOPMENT WILL CEASE LEADING TO MORE OF A
STRATIFORM PRECIPITATION REGIME WITH EMBEDDED CLUSTERS OF HEAVIER
RAINFALL. SHOWER ACTIVITY WILL DECREASE FROM NORTH TO SOUTH AS
UPPER LEVEL IMPULSES EXIT THE REGION ON MONDAY EVENING. THE
OVERNIGHT HOURS OF TUESDAY MORNING SHOULD REMAIN MOSTLY DRY AS MODEL
GUIDANCE INDICATES A LULL IN THE SHOWER ACTIVITY. TEMPERATURES
THROUGH THIS PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE NORMAL FOR LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AT 315 AM EDT MON...A CLIPPER WAVE MOVING SE THROUGH THE MIDWEST ON
TUE WILL SHARPEN UP AN ERN TROUGH AXIS OVER THE APPALACHIANS TUE
NIGHT THROUGH WED. THE NUMERICAL MODELS ALL FEATURE WEAK SFC WAVES
AHEAD OF THE UPPER CLIPPER MOVING EAST ALONG THE LINGERING WEAK
BOUNDARY IN PLACE OVER THE FORECAST AREA. IN ADDITION...THE
STRONGEST RIGHT ENTRANCE REGION UPPER JET DIVERGENCE WILL CROSS THE
FORECAST AREA MAINLY TUE NIGHT INTO WED. THESE VARIOUS FORCING
MECHANISMS WILL COINCIDE WITH A ZONE OF RELATIVELY DEEP MOISTURE
ORIENTED W TO E ACROSS THE AREA TUE THROUGH MUCH OF WED. THIS WILL
REQUIRE SOLID CHC TO LOW END LIKELY POPS THROUGHOUT. THERE IS VERY
LIMITED SHEAR IN THE MODEL PROFILES TUE THROUGH WED...AND SFC BASED
INSTABILITY MAY ALSO BE LIMITED DESPITE THE HIGH DEWPOINTS BECAUSE
OF CLOUD COVER. LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREAT.
WILL CONTINUE TO FEATURE A SMALLER THAN CLIMO DIURNAL RANGE OF WARM
MIN TEMPS AND COOLER THAN NORMAL MAX TEMPS TUE THROUGH WED NIGHT
GIVEN THE CLOUD COVER AND PRECIP CHANCES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 320 AM EDT MONDAY...HEIGHTS WILL BUILD FROM THE W THU THROUGH
FRI AS A LARGE ANTICYCLONE TAKES UP RESIDENCE OVER THE SRN PLAINS.
HOWEVER...ENERGY TOPPING THE RIDGE COULD SPARK MCS ACITIVTY THAT MAY
MAKE A RUN TOWARD THE SRN APPALACHIANS LATE FRI/FRI NIGHT. THIS IS
QUITE UNCERTAIN AT PRESENT...SO WILL KEEP THE THUNDERSTORM FORECAST
ON A MORE TYPICAL SCATTERED DIURNAL PATTERN THU AND FRI AFTNS.
UPPER RIDGING WILL BECOME MORE DOMINANT THROUGH THE WEEKEND.
HOWEVER...LINGERING LOW LEVEL MOISTURE AND A SE ATLANTIC FETCH COULD
LEAD TO MORNING STRATUS EACH DAY. THERE WILL PERSIST A MAINLY
DIURNAL ISOLD TO SCT THUNDERSTORM THREAT...ESPECIALLY OVER THE MTNS.
MAXES WILL STEADILY RISE TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES BY
SUNDAY AFTN.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH
THE ONLY EXCEPTIONS BEING LOWERING VISB ADJACENT TO ANY THUNDERSTORM
DEVELOPMENT ON MONDAY AFTERNOON. EXPECTING CIGS TO LOWER TO AROUND
10KFT AS UPPER SHORTWAVE TROF PASSES THROUGH THIS MORNING.
LIKEWISE...A GRADUAL INCREASE IN COVERAGE OF SHOWER ACTIVITY IS
EXPECTED THUS PROMPTING MENTION OF -SHRA AROUND 15Z. AS SOME
HEATING OCCURS DURING THE EARLY AFTERNOON HOURS...THERE WILL BE A
CHANCE FOR SOME RATHER DISORGANIZED CONVECTION LEADING TO TEMPO FOR
TSRA THROUGH THE AFTERNOON. SOME LOWER BKN CIGS ARE POSSIBLE LATE
IN THE PERIOD DUE TO OVERSPREADING CONVECTIVE DEBRIS. WINDS WILL
GENERALLY BE LIGHT AND SOUTHERLY.
ELSEWHERE...LOOK FOR VFR CONDITIONS TO PERSIST THROUGH THE TAF
PERIOD ASIDE FOR VISB RESTRICTIONS DUE TO THUNDERSTORM DEVELOPMENT
MONDAY AFTERNOON. AS WITH KCLT ABOVE...EXPECTING COVERAGE OF
SHOWERS TO INCREASE THROUGH THE MORNING HOURS IN RESPONSE TO UPPER
TROF. MODELS INDICATE THE BEST INSTABILITY TO BE AROUND THE 15-18Z
TIMEFRAME ACROSS THE FOOTHILLS OF NORTH CAROLINA...AND THE
UPSTATE/PIEDMONT REGIONS OF SOUTH CAROLINA. THUS...WENT WITH TEMPO
GROUPS FOR TSRA AT ALL CORRESPONDING SITES FOR THIS PERIOD. BEYOND
THAT... EXPECTING LESS THUNDERSTORM PERSISTENCE THUS REVERTED TO
-SHRA WITH VCTS MENTION IN THE TAFS. SHOWER ACTIVITY WILL TAPER OFF
FROM NORTH TO SOUTH MONDAY EVENING THEREFORE KEPT VCSH AT ALL SOUTH
CAROLINA SITES. CIGS TUESDAY MORNING SHOULD REMAIN OVC AT AROUND
THE 15KFT LEVEL AT ALL SITES.
OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-15Z
KCLT HIGH 100% HIGH 88% HIGH 94% HIGH 100%
KGSP HIGH 99% HIGH 88% HIGH 91% HIGH 92%
KAVL HIGH 100% HIGH 88% HIGH 84% HIGH 96%
KHKY HIGH 100% HIGH 88% HIGH 94% HIGH 85%
KGMU HIGH 99% HIGH 88% HIGH 93% HIGH 100%
KAND HIGH 100% HIGH 88% HIGH 84% MED 74%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG/SBK
SHORT TERM...HG
LONG TERM...HG
AVIATION...CDG
000
FXUS62 KCHS 171452
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1052 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL BUILD FROM THE NORTH INTO NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MUCH MORE ACTIVE DAY WEATHER-WISE TODAY COMPARED TO THE WEEKEND AS
DEEPER MOISTURE MOVES INTO THE AREA FROM THE WEST IN ASSOCIATION
WITH UPPER SHORTWAVE ENERGY SHIFTING THROUGH THE MOSTLY ZONAL FLOW
ALOFT. ADD IN A FEW BOUNDARIES FROM THE SEA BREEZE...DIFFERENTIAL
HEATING AND CONVECTIVE OUTFLOWS AND COVERAGE OF SHOWERS AND
THUNDERSTORMS LOOKS TO BE PRETTY GOOD. BY LATE AFTERNOON WE SHOULD
BE SEEING NUMEROUS SHOWERS AND THUNDERSTORMS AWAY FROM THE
IMMEDIATE COAST. THE MODIFIED CHS SOUNDING INDICATES SURFACE BASED
CAPE AROUND 1900 J/KG WITH AROUND 1200 J/KG OF DOWNDRAFT CAPE
WHICH WOULD IMPLY A GOOD CHANCE OF DOWNBURSTS WITH THE STRONGEST
CONVECTION. HOWEVER...MODEL FORECAST SOUNDINGS SHOW THE ATMOSPHERE
MOISTENING UP WITH TIME AND THUS THE THREAT SHOULD SHIFT TO WET
MICROBURSTS ALONG WITH SOME LARGE HAIL IN THE STRONGER STORMS.
HIGHS SHOULD BE TEMPERED SOMEWHAT BY THE INCREASED CLOUD COVER
WITH MOST LOCALES LIKELY REACHING THE MID TO UPPER 80S AWAY FROM
THE IMMEDIATE COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...SHOWER/TSTMS ACTIVITY WILL GRADUALLY WIND DOWN AS
INSTABILITY WANES WITH THE LOSS OF INSOLATION AND THE ATMOSPHERE
IS STEADILY OVERTURNED. THERE ARE SOME INDICATIONS THAT
CONVECTION COULD CLUSTER ALONG/NEAR THE ALTAMAHA RIVER EARLY THIS
EVENING AS THE GULF SEA BREEZE MAKES A RUN FOR THE FAR SOUTHERN
ZONES...BUT IT IS UNCLEAR WHETHER THE GULF SEA BREEZE WILL MAKE
IT THIS FAR NORTH. THIS WILL HAVE TO THE WATCHED CAREFULLY. WILL
CARRY 40-60 PERCENT POPS EARLY THIS EVENING...DIMINISHING TO 20-30
PERCENT FORTH OVERNIGHT HOURS. LOWS WILL RANGE FROM AROUND 70 WELL
INLAND TO THE MID 70S AT THE COAST.
TUESDAY...A PROGRESSIVE NEARLY ZONAL PATTERN ALOFT WILL ALLOW A
SERIES OF WEAK SHORTWAVES TO CONTINUALLY MOVE THROUGH THE SOUTHEAST
STATES EARLY IN THE WEEK. AT THE SURFACE...A WAVE OF LOW PRESSURE
WILL DEVELOP ALONG A COLD FRONT STRETCHING FROM APPROXIMATELY
UPSTATE SOUTH CAROLINA THROUGH COASTAL NORTH CAROLINA. THE
COMBINATION OF UPPER LEVEL ENERGY AND DEEP LAYER MOISTURE...ALONG
WITH FRONTAL CONVERGENCE...WILL SUPPORT INCREASING CONVECTIVE
COVERAGE BY TUESDAY AFTERNOON. THE BEST POTENTIAL FOR THUNDERSTORM
ACTIVITY WILL BE ALONG THE FAR INLAND TIER COUNTIES CLOSEST TO THE
LINGERING FRONT...YET SOLID DEEP WESTERLY FLOW SHOULD STILL PUSH
UPSTREAM CONVECTION TOWARD THE COAST. WILL THUS ADVERTISE
THUNDERSTORM CHANCES RANGING FROM 50 TO 60 PERCENT INLAND TO 40
PERCENT CLOSER TO THE COAST DURING THE DAYTIME HOURS. IF THE
CENTER OF THE MAIN SURFACE WAVE SLIPS TOWARD THE OUTER BANKS OF
NORTH CAROLINA LATE TUESDAY NIGHT...THEN SHOWER/THUNDERSTORM
COVERAGE WILL DECREASE FROM SOUTH TO NORTH AFTER MIDNIGHT.
SUFFICIENT SYNOPTIC SCALE FORCING WILL STILL MAINTAIN CHANCES IN
THE 20 PERCENT RANGE SOUTHEAST GEORGIA TO THE 30 TO 40 PERCENT
RANGE CHARLESTON TRI COUNTY REGION TOWARD THE PRE DAWN HOURS. HIGH
TEMPERATURES WILL REACH THE UPPER 80S TO AROUND 90 DEGREES AWAY
FROM THE LOCALLY COOLER COASTLINE.
WEDNESDAY...CONVECTIVE COVERAGE WILL SURGE AGAIN AFTER
DAYBREAK...AS THE AMPLIFYING SHORTWAVE TROUGH MOVING OVER THE EAST
COAST PULLS THE FRONT DIRECTLY INTO THE FORECAST AREA DURING THE
AFTERNOON HOURS. HAVE INDICATED HIGHEST THUNDERSTORM POTENTIAL OF
THE PERIOD ON WEDNESDAY...WITH LIKELY POPS FOR THE MAJORITY OF
THE ZONES AWAY FROM THE COASTLINE. THE AXIS OF THE LOW PRESSURE
WAVE WILL SHIFT INTO THE MARINE ZONES WITH THE MAIN SHORTWAVE
OVERNIGHT...PULLING DEEPEST MOISTURE AND ASSOCIATED CONVECTIVE
ACTIVITY TOWARD THE EASTERN HALF OF THE FORECAST AREA AND THE
COASTAL WATERS. HIGH TEMPERATURES ON WEDNESDAY WILL BE A BIT
TRICKY...ESPECIALLY ACROSS NORTHERN AREAS THAT COULD END UP ON THE
COOL SIDE OF THE DESCENDING FRONT. WILL INDICATE MID TO UPPER 80S
NORTHERN MOST ZONES AND UPPER 80S TO AROUND 90 FARTHER SOUTH.
THURSDAY...THE WEAK COLD FRONT WILL CONTINUE TO SLIP SOUTH THROUGH
THE FORECAST AREA EARLY IN THE DAY...BEFORE STALLING ALONG THE
SOUTHERN PERIPHERY AS IT BECOMES MORE PARALLEL TO FLOW ALOFT.
THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND ECMWF MODEL
SOLUTIONS REGARDING PRECIPITATION COVERAGE...A RESULT OF THE GFS
MAINTAINING A MORE PROMINENT UPPER TROUGH OVER THE SOUTHEAST
STATES. HAVE OPTED TO MAINTAIN SOLID THUNDERSTORM CHANCES ACROSS
THE AREA FOR THE AFTERNOON PERIOD...INDICATING SLIGHTLY HIGHER
POTENTIAL ACROSS THE SOUTHERN SECTIONS CLOSEST TO THE STALLED
BOUNDARY. HIGH TEMPERATURES COULD ONCE AGAIN REFLECT A SLIGHT
NORTHEAST/SOUTHWEST GRADIENT...WITH SUBTLE COOLER CONDITIONS IN
THE MID TO UPPER 80S CHARLESTON TRI COUNTY REGION COMPARED TO
AROUND 90 DEGREES FARTHER SOUTH NEAR THE ALTAMAHA RIVER.
OVERALL SEVERE POTENTIAL LOOKS LOW THROUGH THE PERIOD...AS THE
STRONGEST SYNOPTIC FORCING AND WIND FIELDS REMAIN NORTH OF THE
FORECAST AREA. HOWEVER...AS IS TYPICAL THIS TIME OF YEAR...AN
ISOLATED STRONG TO SEVERE THUNDERSTORM IS POSSIBLE WHERE BOUNDARY
INTERACTIONS OCCUR AND ENHANCE UPDRAFT STRENGTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
GENERALLY VFR. RISK FOR SHOWERS/TSTMS WILL INCREASE LATER THIS
MORNING AND INTO THE AFTERNOON DUE TO SEVERAL BOUNDARIES INCLUDING
THE SEA BREEZE...DIFFERENTIAL HEATING AND CONVECTIVE OUTFLOWS.
AMENDMENTS WILL MOST CERTAINLY BE NEEDED THROUGHOUT THE DAY AS
MESOSCALE AND SHORT TERM RADAR TRENDS BECOME MORE APPARENT.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS MONDAY NIGHT
THROUGH THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA.
&&
.MARINE...
TODAY...SOUTHERLY WIND REGIME WILL PERSIST WITH WINDS GENERALLY 10
KT OR LESS...POSSIBLY CLOSER TO 15 KT ALONG THE COAST WITH THE SEA
BREEZE...AND SEAS 2-4 FT...HIGHEST E.
TONIGHT...WINDS WILL INCREASE SLIGHTLY AHEAD OF AN APPROACHING
COLD FRONT. SPEEDS COULD REACH AS HIGH AS 15-20 KT AT TIMES WITH
SEAS 2-4 FT. SMALL CRAFT ADVISORY CONDITIONS ARE UNLIKELY AT THIS
TIME.
TUESDAY THROUGH FRIDAY...THE MARINE ZONES WILL BECOME SITUATED
BETWEEN AN APPROACHING COLD FRONT/SURFACE TROUGH INLAND AND
RETREATING HIGH PRESSURE TO THE EAST EARLY THIS WEEK. SOUTHERLY
FLOW WILL SURGE SLIGHTLY BY WEDNESDAY AS THE PRESSURE GRADIENT
TIGHTENS BETWEEN THE TWO FEATURES...SUPPORTING A BRIEF PERIOD OF
15 TO 20 KT WINDS AND SEAS UP TO 5 FT BEYOND 20 NM. EXPECT WIND
DIRECTIONS TO VEER WEST/NORTHWEST AS THE FRONT STEADILY SLIPS INTO
THE FORECAST AREA THURSDAY...AS SPEEDS DIMINISH A BIT WITHIN A
WEAKENING PRESSURE GRADIENT. NUMERICAL MODEL SOLUTIONS DIFFER
REGARDING THE PRECISE LOCATION OF THE STALLING FRONT BY LATE
WEEK...AND WILL LEAN TOWARD PERSISTENCE IN INDICATING A GENERAL
EAST/NORTHEAST FLOW FOR THURSDAY AND FRIDAY. WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY CONDITIONS THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...RJB
SHORT TERM...ST/WMS
LONG TERM...WMS
AVIATION...RJB/WMS
MARINE...ST/WMS
000
FXUS62 KCAE 171328
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
928 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID LEVEL SHORT WAVE PUSHING EAST THIS AFTERNOON. CONVECTIVE
ACTIVITY EASTERN PART MAY BE INITIATED BY A SEA BREEZE THIS
AFTERNOON. COVERAGE OF SHOWERS AND A FEW THUNDERSTORMS WEST
PART IS DIMINISHING LATE THIS MORNING AS SHORT WAVE IS GONE
IN THAT LOCATION. HIGH RESOLUTION MODELS POINT TOWARD A DECREASE
IN ACTIVITY LATE THIS MORNING AND EARLY THIS AFTERNOON IN THE
WEST PART. IT LOOKS LIKE THE CHANCES SHOULD BE FAIRLY HIGH IN
THE EAST BUT DUE TO UNCERTAINTY AS TO TIMING...DECIDED TO KEEP
THE GOING POPS. OTHERWISE...THE NAM AND GFS SHOW PRECIPITABLE
WATER AROUND 2 INCHES THIS AFTERNOON. THE HIGH MOISTURE AND
HEATING SHOULD HELP SUPPORT THUNDERSTORMS BUT COVERAGE MAY BE
LIMITED SINCE SHORT WAVE WILL BE GONE. THE HIGH RESOLUTION MODELS
INDICATE SCATTERED COVERAGE. CLOUDINESS SHOULD LIMIT INSTABILITY
TODAY. THE NAM DISPLAYS SURFACE-BASED LI/S -4 TO -5 TODAY. THE
THREAT OF SEVERE THUNDERSTORMS APPEARS LOW BECAUSE OF THE LIMITED
INSTABILITY. AN AVERAGE OF THE NAM AND GFS PLUS THE SREF MEAN
SUPPORT GENERAL RAIN AMOUNTS NEAR ONE-HALF OF AN INCH. HEAVY RAIN
MAY OCCUR BECAUSE OF THE HIGH PRECIPITABLE WATER AND POSSIBLE
TRAINING. LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE TODAY
BECAUSE OF CLOUDINESS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
HIGH MOISTURE ASSOCIATED WITH THE DIFFUSE EAST-WEST ORIENTED FRONT
WILL CONTINUE. THE MODELS KEEP BROAD UPPER-LEVEL TROUGHING WITH A
SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS. LEANED
TOWARD THE HIGHER GUIDANCE POPS. THE COOLER HIGH TEMPERATURE
GUIDANCE APPEARS BETTER BECAUSE OF EXPECTED CLOUDINESS. THE LOW
TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY THE FRONT REMAINING NEAR THE FORECAST
AREA THROUGH THE MEDIUM-RANGE PERIOD. THERE HAS BEEN INCONSISTENCY
IN THE PLACEMENT OF DEEPER MOISTURE. THE GFS ENSEMBLE MEANS AND
OPERATIONAL GFS MOS SUPPORT CHANCE POPS THROUGH THE PERIOD.
EXPECT HIGH TEMPERATURES NEAR OR A LITTLE BELOW CLIMATOLOGY.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
A WEAK SHORTWAVE MOVING EAST CAUSING SOME SCATTERED SHOWERS AND
MAYBE A FEW THUNDERSTORMS. MAINLY VFR CONDITIONS. WILL LEAVE OUT
IFR-MVFR TAF SITES DUE TO UNCERTAINTY AS TO TIMING AND COVERAGE
ISSUES...BUT BRIEF IFR-MVFR CONDITIONS ARE POSSIBLE IN CONVECTIVE
ACTIVITY. OTHERWISE...A DEEPENING UPPER TROUGH AND INCREASING
ATMOSPHERIC MOISTURE IS EXPECTED TO LEAD TO SCATTERED
THUNDERSTORMS MONDAY AFTERNOON...MAINLY AFTER 18Z. HAVE MENTION
SHRA AFTER 21Z AT ALL TAF SITES BUT TSRA MAY BE POSSIBLE AS WELL.
WILL CONTINUE MENTION OF SHRA IN THE TAFS TOWARDS THE END OF THE
TAF PERIOD AS A SLOW- MOVING COLD FRONT APPROACHES FROM THE OH
RIVER VALLEY.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 171132
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
732 AM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EDT MONDAY...SCATTERED SHOWER ACTIVITY CONTINUES ACROSS
PORTIONS OF THE NORTH AND SOUTH CAROLINA PIEDMONTS. EXPECTING THIS
ACTIVITY TO CONTINUE MOVING EASTWARD THROUGHOUT THE MORNING.
ELSEWHERE...MORE SHOWERS WILL BE MOVING IN FROM THE WEST AND
INCREASING IN COVERAGE LATER IN THE MORNING. THEREFORE...UPDATED
NEAR TERM POPS TO REFLECT RECENT RADAR TRENDS AND ADJUSTED
TEMPERATURES ACCORDING TO RECENT OBSERVATIONS. OTHERWISE...NO OTHER
CHANGES WERE MADE.
PREVIOUS DISCUSSION...
AS OF 250 AM EDT MONDAY...CURRENT RADAR TRENDS INDICATE A LARGE
SHIELD OF STRATIFORM PRECIPITATION LOCATED ACROSS NORTHEAST GEORGIA
AND THE WESTERN UPSTATE REGION OF SOUTH CAROLINA. OTHERWISE...BROAD
CYCLONIC FLOW WILL PROMOTE CONTINUED SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE PERIOD. SHORT RANGE MODEL GUIDANCE INDICATES A
SERIES OF MID-UPPER LEVEL VORTICITY MAXIMA PASSING THROUGH THE
REGION OVER THE NEXT 18-24 HOURS. IN RESPONSE...A MILDLY UNSTABLE
AIRMASS AT THE SURFACE WILL PROVIDE ENOUGH LOW LEVEL LIFTING
POTENTIAL FOR SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT MONDAY
MORNING. SOUNDINGS INDICATE SBCAPE VALUES GENERALLY RANGING FROM
500-1000 J/KG WITH THE HIGHEST VALUES LYING ACROSS WESTERN NORTH
CAROLINA DUE TO CURRENT SHOWER ACTIVITY WORKING OVER THE ATMOSPHERE
ACROSS THE UPSTATE AND NORTHEAST GEORGIA. BY LATE MORNING TO EARLY
AFTERNOON...EXPECTING SKY COVER TO INCREASE AS THE COLUMN MOISTENS
THEREBY DECREASING SURFACE HEATING. WITH THAT...MOST IF NOT ALL
ISOLATED THUNDERSTORM DEVELOPMENT WILL CEASE LEADING TO MORE OF A
STRATIFORM PRECIPITATION REGIME WITH EMBEDDED CLUSTERS OF HEAVIER
RAINFALL. SHOWER ACTIVITY WILL DECREASE FROM NORTH TO SOUTH AS
UPPER LEVEL IMPULSES EXIT THE REGION ON MONDAY EVENING. THE
OVERNIGHT HOURS OF TUESDAY MORNING SHOULD REMAIN MOSTLY DRY AS MODEL
GUIDANCE INDICATES A LULL IN THE SHOWER ACTIVITY. TEMPERATURES
THROUGH THIS PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE NORMAL FOR LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AT 315 AM EDT MON...A CLIPPER WAVE MOVING SE THROUGH THE MIDWEST ON
TUE WILL SHARPEN UP AN ERN TROUGH AXIS OVER THE APPALACHIANS TUE
NIGHT THROUGH WED. THE NUMERICAL MODELS ALL FEATURE WEAK SFC WAVES
AHEAD OF THE UPPER CLIPPER MOVING EAST ALONG THE LINGERING WEAK
BOUNDARY IN PLACE OVER THE FORECAST AREA. IN ADDITION...THE
STRONGEST RIGHT ENTRANCE REGION UPPER JET DIVERGENCE WILL CROSS THE
FORECAST AREA MAINLY TUE NIGHT INTO WED. THESE VARIOUS FORCING
MECHANISMS WILL COINCIDE WITH A ZONE OF RELATIVELY DEEP MOISTURE
ORIENTED W TO E ACROSS THE AREA TUE THROUGH MUCH OF WED. THIS WILL
REQUIRE SOLID CHC TO LOW END LIKELY POPS THROUGHOUT. THERE IS VERY
LIMITED SHEAR IN THE MODEL PROFILES TUE THROUGH WED...AND SFC BASED
INSTABILITY MAY ALSO BE LIMITED DESPITE THE HIGH DEWPOINTS BECAUSE
OF CLOUD COVER. LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREAT.
WILL CONTINUE TO FEATURE A SMALLER THAN CLIMO DIURNAL RANGE OF WARM
MIN TEMPS AND COOLER THAN NORMAL MAX TEMPS TUE THROUGH WED NIGHT
GIVEN THE CLOUD COVER AND PRECIP CHANCES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 320 AM EDT MONDAY...HEIGHTS WILL BUILD FROM THE W THU THROUGH
FRI AS A LARGE ANTICYCLONE TAKES UP RESIDENCE OVER THE SRN PLAINS.
HOWEVER...ENERGY TOPPING THE RIDGE COULD SPARK MCS ACITIVTY THAT MAY
MAKE A RUN TOWARD THE SRN APPALACHIANS LATE FRI/FRI NIGHT. THIS IS
QUITE UNCERTAIN AT PRESENT...SO WILL KEEP THE THUNDERSTORM FORECAST
ON A MORE TYPICAL SCATTERED DIURNAL PATTERN THU AND FRI AFTNS.
UPPER RIDGING WILL BECOME MORE DOMINANT THROUGH THE WEEKEND.
HOWEVER...LINGERING LOW LEVEL MOISTURE AND A SE ATLANTIC FETCH COULD
LEAD TO MORNING STRATUS EACH DAY. THERE WILL PERSIST A MAINLY
DIURNAL ISOLD TO SCT THUNDERSTORM THREAT...ESPECIALLY OVER THE MTNS.
MAXES WILL STEADILY RISE TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES BY
SUNDAY AFTN.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH
THE ONLY EXCEPTIONS BEING LOWERING VISB ADJACENT TO ANY THUNDERSTORM
DEVELOPMENT ON MONDAY AFTERNOON. EXPECTING CIGS TO LOWER TO AROUND
10KFT AS UPPER SHORTWAVE TROF PASSES THROUGH THIS MORNING.
LIKEWISE...A GRADUAL INCREASE IN COVERAGE OF SHOWER ACTIVITY IS
EXPECTED THUS PROMPTING MENTION OF -SHRA AROUND 15Z. AS SOME
HEATING OCCURS DURING THE EARLY AFTERNOON HOURS...THERE WILL BE A
CHANCE FOR SOME RATHER DISORGANIZED CONVECTION LEADING TO TEMPO FOR
TSRA THROUGH THE AFTERNOON. SOME LOWER BKN CIGS ARE POSSIBLE LATE
IN THE PERIOD DUE TO OVERSPREADING CONVECTIVE DEBRIS. WINDS WILL
GENERALLY BE LIGHT AND SOUTHERLY.
ELSEWHERE...LOOK FOR VFR CONDITIONS TO PERSIST THROUGH THE TAF
PERIOD ASIDE FOR VISB RESTRICTIONS DUE TO THUNDERSTORM DEVELOPMENT
MONDAY AFTERNOON. AS WITH KCLT ABOVE...EXPECTING COVERAGE OF
SHOWERS TO INCREASE THROUGH THE MORNING HOURS IN RESPONSE TO UPPER
TROF. MODELS INDICATE THE BEST INSTABILITY TO BE AROUND THE 15-18Z
TIMEFRAME ACROSS THE FOOTHILLS OF NORTH CAROLINA...AND THE
UPSTATE/PIEDMONT REGIONS OF SOUTH CAROLINA. THUS...WENT WITH TEMPO
GROUPS FOR TSRA AT ALL CORRESPONDING SITES FOR THIS PERIOD. BEYOND
THAT... EXPECTING LESS THUNDERSTORM PERSISTENCE THUS REVERTED TO
-SHRA WITH VCTS MENTION IN THE TAFS. SHOWER ACTIVITY WILL TAPER OFF
FROM NORTH TO SOUTH MONDAY EVENING THEREFORE KEPT VCSH AT ALL SOUTH
CAROLINA SITES. CIGS TUESDAY MORNING SHOULD REMAIN OVC AT AROUND
THE 15KFT LEVEL AT ALL SITES.
OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 100% HIGH 100% HIGH 83% HIGH 100%
KGSP HIGH 97% HIGH 100% HIGH 83% HIGH 91%
KAVL HIGH 95% HIGH 100% HIGH 80% HIGH 83%
KHKY HIGH 100% HIGH 100% HIGH 83% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 83% HIGH 100%
KAND HIGH 87% HIGH 100% HIGH 83% HIGH 80%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG
SHORT TERM...HG
LONG TERM...HG
AVIATION...CDG
000
FXUS62 KCHS 171102
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
702 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL BUILD FROM THE NORTH INTO NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FORECAST IS ON TRACK. NO MAJOR CHANGES WERE MADE WITH THE
SUNRISE UPDATE.
TODAY...IT LOOKS TO BE CONVECTIVELY ACTIVE DAY AS THE UPPER RIDGE
RAPIDLY BREAKS DOWN AND THE WESTERN FLANKS OF ATLANTIC HIGH
PRESSURE BUCKLES. FILTERED SUNSHINE THIS MORNING WILL ALLOW
TEMPERATURES TO WARM QUICKLY INTO THE UPPER 80S FOR MOST
LOCATIONS AWAY FROM THE COAST WITH MODIFIED BUFR SOUNDINGS
SUPPORTING CONVECTIVE TEMPERATURES AROUND 84-85 DEGREES. THE
PRIMARY FOCI FOR TSTMS TO DEVELOP TODAY WILL BE ALONG A SOMEWHAT
ILL-DEFINED SEA BREEZE AND A CONVECTIVE OUTFLOW BOUNDARY THAT CAN
BE SEEN EMERGING FROM THE CONVECTION OVER NORTHERN GEORGIA EARLY
THIS MORNING. THE VARIOUS LAKE BREEZE CIRCULATIONS AROUND THE
SANTEE-COOPER LAKES COULD ALSO COME INTO PLAY AS THE AFOREMENTIONED
OUTFLOW BECOMES ALIGNED SOUTHWEST-NORTHEAST ACROSS THE INTERIOR
SOUTHEAST SOUTH CAROLINA ZONES BY EARLY AFTERNOON.
THERE LOOKS TO BE A PRETTY HEALTHY COVERAGE OF SHOWERS/TSTMS
DURING PEAK HEATING SO WILL BUMP POPS UP SLIGHTLY TO 60 PERCENT
AWAY FROM THE BEACHES...WHICH WILL LINGER INTO THE EARLY EVENING
HOURS. SHEAR IS WEAK AND INSTABILITY PROGNOSTICATIONS ARE NOT ALL
THAT IMPRESSIVE SO THE RISK FOR SEVERE WEATHER LOOKS TO BE PRETTY
LOW...HOWEVER AN ISOLATED WET MICROBURST OR TWO CAN NOT BE
COMPLETELY RULED OUT WHERE UPDRAFTS BECOME ENHANCED BY MESOSCALE
BOUNDARY INTERACTIONS. SHOWER/TSTMS ACTIVITY IS EXPECTED TO SLOWLY
FORM/REFORM ACROSS INTERIOR SOUTHEAST GEORGIA BY LATE AFTERNOON...
POSSIBLY BECOMING ENHANCED BY ADDITIONAL CONVECTIVE OUTFLOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...SHOWER/TSTMS ACTIVITY WILL GRADUALLY WIND DOWN AS
INSTABILITY WANES WITH THE LOSS OF INSOLATION AND THE ATMOSPHERE
IS STEADILY OVERTURNED. THERE ARE SOME INDICATIONS THAT
CONVECTION COULD CLUSTER ALONG/NEAR THE ALTAMAHA RIVER EARLY THIS
EVENING AS THE GULF SEA BREEZE MAKES A RUN FOR THE FAR SOUTHERN
ZONES...BUT IT IS UNCLEAR WHETHER THE GULF SEA BREEZE WILL MAKE
IT THIS FAR NORTH. THIS WILL HAVE TO THE WATCHED CAREFULLY. WILL
CARRY 40-60 PERCENT POPS EARLY THIS EVENING...DIMINISHING TO 20-30
PERCENT FORTH OVERNIGHT HOURS. LOWS WILL RANGE FROM AROUND 70 WELL
INLAND TO THE MID 70S AT THE COAST.
TUESDAY...A PROGRESSIVE NEARLY ZONAL PATTERN ALOFT WILL ALLOW A
SERIES OF WEAK SHORTWAVES TO CONTINUALLY MOVE THROUGH THE SOUTHEAST
STATES EARLY IN THE WEEK. AT THE SURFACE...A WAVE OF LOW PRESSURE
WILL DEVELOP ALONG A COLD FRONT STRETCHING FROM APPROXIMATELY
UPSTATE SOUTH CAROLINA THROUGH COASTAL NORTH CAROLINA. THE
COMBINATION OF UPPER LEVEL ENERGY AND DEEP LAYER MOISTURE...ALONG
WITH FRONTAL CONVERGENCE...WILL SUPPORT INCREASING CONVECTIVE
COVERAGE BY TUESDAY AFTERNOON. THE BEST POTENTIAL FOR THUNDERSTORM
ACTIVITY WILL BE ALONG THE FAR INLAND TIER COUNTIES CLOSEST TO THE
LINGERING FRONT...YET SOLID DEEP WESTERLY FLOW SHOULD STILL PUSH
UPSTREAM CONVECTION TOWARD THE COAST. WILL THUS ADVERTISE
THUNDERSTORM CHANCES RANGING FROM 50 TO 60 PERCENT INLAND TO 40
PERCENT CLOSER TO THE COAST DURING THE DAYTIME HOURS. IF THE
CENTER OF THE MAIN SURFACE WAVE SLIPS TOWARD THE OUTER BANKS OF
NORTH CAROLINA LATE TUESDAY NIGHT...THEN SHOWER/THUNDERSTORM
COVERAGE WILL DECREASE FROM SOUTH TO NORTH AFTER MIDNIGHT.
SUFFICIENT SYNOPTIC SCALE FORCING WILL STILL MAINTAIN CHANCES IN
THE 20 PERCENT RANGE SOUTHEAST GEORGIA TO THE 30 TO 40 PERCENT
RANGE CHARLESTON TRI COUNTY REGION TOWARD THE PRE DAWN HOURS. HIGH
TEMPERATURES WILL REACH THE UPPER 80S TO AROUND 90 DEGREES AWAY
FROM THE LOCALLY COOLER COASTLINE.
WEDNESDAY...CONVECTIVE COVERAGE WILL SURGE AGAIN AFTER
DAYBREAK...AS THE AMPLIFYING SHORTWAVE TROUGH MOVING OVER THE EAST
COAST PULLS THE FRONT DIRECTLY INTO THE FORECAST AREA DURING THE
AFTERNOON HOURS. HAVE INDICATED HIGHEST THUNDERSTORM POTENTIAL OF
THE PERIOD ON WEDNESDAY...WITH LIKELY POPS FOR THE MAJORITY OF
THE ZONES AWAY FROM THE COASTLINE. THE AXIS OF THE LOW PRESSURE
WAVE WILL SHIFT INTO THE MARINE ZONES WITH THE MAIN SHORTWAVE
OVERNIGHT...PULLING DEEPEST MOISTURE AND ASSOCIATED CONVECTIVE
ACTIVITY TOWARD THE EASTERN HALF OF THE FORECAST AREA AND THE
COASTAL WATERS. HIGH TEMPERATURES ON WEDNESDAY WILL BE A BIT
TRICKY...ESPECIALLY ACROSS NORTHERN AREAS THAT COULD END UP ON THE
COOL SIDE OF THE DESCENDING FRONT. WILL INDICATE MID TO UPPER 80S
NORTHERN MOST ZONES AND UPPER 80S TO AROUND 90 FARTHER SOUTH.
THURSDAY...THE WEAK COLD FRONT WILL CONTINUE TO SLIP SOUTH THROUGH
THE FORECAST AREA EARLY IN THE DAY...BEFORE STALLING ALONG THE
SOUTHERN PERIPHERY AS IT BECOMES MORE PARALLEL TO FLOW ALOFT.
THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND ECMWF MODEL
SOLUTIONS REGARDING PRECIPITATION COVERAGE...A RESULT OF THE GFS
MAINTAINING A MORE PROMINENT UPPER TROUGH OVER THE SOUTHEAST
STATES. HAVE OPTED TO MAINTAIN SOLID THUNDERSTORM CHANCES ACROSS
THE AREA FOR THE AFTERNOON PERIOD...INDICATING SLIGHTLY HIGHER
POTENTIAL ACROSS THE SOUTHERN SECTIONS CLOSEST TO THE STALLED
BOUNDARY. HIGH TEMPERATURES COULD ONCE AGAIN REFLECT A SLIGHT
NORTHEAST/SOUTHWEST GRADIENT...WITH SUBTLE COOLER CONDITIONS IN
THE MID TO UPPER 80S CHARLESTON TRI COUNTY REGION COMPARED TO
AROUND 90 DEGREES FARTHER SOUTH NEAR THE ALTAMAHA RIVER.
OVERALL SEVERE POTENTIAL LOOKS LOW THROUGH THE PERIOD...AS THE
STRONGEST SYNOPTIC FORCING AND WIND FIELDS REMAIN NORTH OF THE
FORECAST AREA. HOWEVER...AS IS TYPICAL THIS TIME OF YEAR...AN
ISOLATED STRONG TO SEVERE THUNDERSTORM IS POSSIBLE WHERE BOUNDARY
INTERACTIONS OCCUR AND ENHANCE UPDRAFT STRENGTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
GENERALLY VFR. RISK FOR SHOWERS/TSTMS WILL INCREASE LATER THIS
MORNING AND INTO THE AFTERNOON. MODELS GENERALLY FAVOR THE
CORRIDOR OF GREATEST COVERAGE REMAINING TO THE WEST OF THE KCHS-
KSAV CORRIDOR...ALTHOUGH SOME OF THE HIGHER RESOLUTION DATA
SUGGEST KCHS MAY HAVE A BETTER SHOW LATER THIS AFTERNOON FOR
IMPACTS. WILL TEMPO 19-21Z FOR 4SM TSRA BR SCT015 BKN035CB TO
COVER FOR NOW. WILL LEAVE TSRA OUT OF THE KSAV TAF UNTIL CONFIDENCE
INCREASES. AMENDMENTS WILL MOST CERTAINLY BE NEEDED THROUGHOUT
THE DAY AS MESOSCALE AND SHORT TERM RADAR TRENDS BECOME MORE
APPARENT.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS MONDAY NIGHT
THROUGH THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA.
&&
.MARINE...
TODAY...SOUTHERLY WIND REGIME WILL PERSIST WITH WINDS GENERALLY 10
KT OR LESS AND SEAS 2-4 FT.
TONIGHT...WINDS WILL INCREASE SLIGHTLY AHEAD OF AN APPROACHING
COLD FRONT. SPEEDS COULD REACH AS HIGH AS 15-20 KT AT TIMES WITH
SEAS 2-4 FT. SMALL CRAFT ADVISORY CONDITIONS ARE UNLIKELY AT THIS
TIME.
TUESDAY THROUGH FRIDAY...THE MARINE ZONES WILL BECOME SITUATED
BETWEEN AN APPROACHING COLD FRONT/SURFACE TROUGH INLAND AND
RETREATING HIGH PRESSURE TO THE EAST EARLY THIS WEEK. SOUTHERLY
FLOW WILL SURGE SLIGHTLY BY WEDNESDAY AS THE PRESSURE GRADIENT
TIGHTENS BETWEEN THE TWO FEATURES...SUPPORTING A BRIEF PERIOD OF
15 TO 20 KT WINDS AND SEAS UP TO 5 FT BEYOND 20 NM. EXPECT WIND
DIRECTIONS TO VEER WEST/NORTHWEST AS THE FRONT STEADILY SLIPS INTO
THE FORECAST AREA THURSDAY...AS SPEEDS DIMINISH A BIT WITHIN A
WEAKENING PRESSURE GRADIENT. NUMERICAL MODEL SOLUTIONS DIFFER
REGARDING THE PRECISE LOCATION OF THE STALLING FRONT BY LATE
WEEK...AND WILL LEAN TOWARD PERSISTENCE IN INDICATING A GENERAL
EAST/NORTHEAST FLOW FOR THURSDAY AND FRIDAY. WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY CONDITIONS THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/WMS
000
FXUS62 KCAE 171017
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
617 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MID-LEVEL SHORTWAVE TROUGH APPROACHING THE FORECAST AREA THIS
MORNING HAS REMOVED THE CAPPING THAT HAS BEEN DOMINATE DURING THE
PAST FEW DAYS. MOISTURE HAS INCREASED AHEAD OF THE DIFFUSE FRONT
DROPPING SOUTHWARD AND TOWARD THE FORECAST AREA. BELIEVE THE
SHOWERS MOVING INTO THE FORECAST AREA FROM THE WEST EARLY THIS
MORNING ARE MAINLY ASSOCIATED WITH THE MID-LEVEL SHORTWAVE
TROUGH. THE HIGH-RESOLUTION MODELS SHOW COVERAGE DIMINISHING AS
THESE SHOWERS MOVE INTO THE FORECAST AREA THIS MORNING. THEREFORE...
WE DID NOT FORECAST CATEGORICAL POPS THROUGHOUT THE AREA.
FORECASTED POPS OF 50 TO NEAR 100 PERCENT WITH THE HIGHEST POPS
FOR NOW IN THE SOUTHWEST PART BASED ON RADAR TRENDS AND HRRR MODEL.
THE NAM AND GFS SHOW PRECIPITABLE WATER AROUND 2 INCHES THIS
AFTERNOON. THE HIGH MOISTURE AND HEATING SHOULD HELP SUPPORT
THUNDERSTORMS BUT COVERAGE MAY BE LIMITED BECAUSE LIFT ASSOCIATED
THIS MORNING/S SHORTWAVE TROUGH SHOULD BE EAST OF THE FORECAST
AREA. THE HIGH RESOLUTION MODELS INDICATE SCATTERED COVERAGE.
CLOUDINESS SHOULD LIMIT INSTABILITY TODAY. THE NAM DISPLAYS
SURFACE-BASED LI/S -4 TO -5 TODAY. THE THREAT OF SEVERE
THUNDERSTORMS APPEARS LOW BECAUSE OF THE LIMITED INSTABILITY. AN
AVERAGE OF THE NAM AND GFS PLUS THE SREF MEAN SUPPORT GENERAL RAIN
AMOUNTS NEAR ONE-HALF OF AN INCH. HEAVY RAIN MAY OCCUR BECAUSE OF
THE HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING. LEANED TOWARD
THE COOLER TEMPERATURE GUIDANCE TODAY BECAUSE OF CLOUDINESS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
HIGH MOISTURE ASSOCIATED WITH THE DIFFUSE EAST-WEST ORIENTED FRONT
WILL CONTINUE. THE MODELS KEEP BROAD UPPER-LEVEL TROUGHING WITH A
SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS. LEANED
TOWARD THE HIGHER GUIDANCE POPS. THE COOLER HIGH TEMPERATURE
GUIDANCE APPEARS BETTER BECAUSE OF EXPECTED CLOUDINESS. THE LOW
TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY THE FRONT REMAINING NEAR THE FORECAST
AREA THROUGH THE MEDIUM-RANGE PERIOD. THERE HAS BEEN INCONSISTENCY
IN THE PLACEMENT OF DEEPER MOISTURE. THE GFS ENSEMBLE MEANS AND
OPERATIONAL GFS MOS SUPPORT CHANCE POPS THROUGH THE PERIOD.
EXPECT HIGH TEMPERATURES NEAR OR A LITTLE BELOW CLIMATOLOGY.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
A WEAK SHORTWAVE CONTINUES TO MAINTAIN AN AREA OF SHOWERS WITH A FEW
EMBEDDED THUNDERSTORMS CURRENTLY OVER NORTHERN GA MOVING EASTWARD.
SOME OF THE SHOWERS MAY MOVE OVER AGS/DNL. WILL INCLUDE A TEMPO
GROUP FOR BOTH AGS AND DNL FOR SHRA UNTIL 14Z. AFTER ANY MORNING
RESTRICTIONS...VFR EXPECTED TODAY OUTSIDE OF ANY CONVECTION. A
DEEPENING UPPER TROUGH AND INCREASING ATMOSPHERIC MOISTURE IS
EXPECTED TO LEAD TO SCATTERED THUNDERSTORMS MONDAY
AFTERNOON...MAINLY AFTER 18Z. HAVE MENTION SHRA AFTER 21Z AT ALL
TAF SITES BUT TSRA MAY BE POSSIBLE AS WELL. WILL CONTINUE MENTION
OF SHRA IN THE TAFS TOWARDS THE END OF THE TAF PERIOD AS A SLOW-
MOVING COLD FRONT APPROACHES FROM THE OH RIVER VALLEY.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 171012
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
612 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MID-LEVEL SHORTWAVE TROUGH APPROACHING THE FORECAST AREA THIS
MORNING HAS REMOVED THE CAPPING THAT HAS BEEN DOMINATE DURING THE
PAST FEW DAYS. MOISTURE HAS INCREASED AHEAD OF THE DIFFUSE FRONT
DROPPING SOUTHWARD AND TOWARD THE FORECAST AREA. BELIEVE THE
SHOWERS MOVING INTO THE FORECAST AREA FROM THE WEST EARLY THIS
MORNING ARE MAINLY ASSOCIATED WITH THE MID-LEVEL SHORTWAVE
TROUGH. THE HIGH-RESOLUTION MODELS SHOW COVERAGE DIMINISHING AS
THESE SHOWERS MOVE INTO THE FORECAST AREA THIS MORNING. THEREFORE...
WE DID NOT FORECAST CATEGORICAL POPS THROUGHOUT THE AREA.
FORECASTED POPS OF 50 TO NEAR 100 PERCENT WITH THE HIGHEST POPS
FOR NOW IN THE SOUTHWEST PART BASED ON RADAR TRENDS AND HRRR MODEL.
THE NAM AND GFS SHOW PRECIPITABLE WATER AROUND 2 INCHES THIS
AFTERNOON. THE HIGH MOISTURE AND HEATING SHOULD HELP SUPPORT
THUNDERSTORMS BUT COVERAGE MAY BE LIMITED BECAUSE LIFT ASSOCIATED
THIS MORNING/S SHORTWAVE TROUGH SHOULD BE EAST OF THE FORECAST
AREA. THE HIGH RESOLUTION MODELS INDICATE SCATTERED COVERAGE.
CLOUDINESS SHOULD LIMIT INSTABILITY TODAY. THE NAM DISPLAYS
SURFACE-BASED LI/S -4 TO -5 TODAY. THE THREAT OF SEVERE
THUNDERSTORMS APPEARS LOW BECAUSE OF THE LIMITED INSTABILITY. AN
AVERAGE OF THE NAM AND GFS PLUS THE SREF MEAN SUPPORT GENERAL RAIN
AMOUNTS NEAR ONE-HALF OF AN INCH. HEAVY RAIN MAY OCCUR BECAUSE OF
THE HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING. LEANED TOWARD
THE COOLER TEMPERATURE GUIDANCE TODAY BECAUSE OF CLOUDINESS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
HIGH MOISTURE ASSOCIATED WITH THE DIFFUSE EAST-WEST ORIENTED FRONT
WILL CONTINUE. THE MODELS KEEP BROAD UPPER-LEVEL TROUGHING WITH A
SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS. LEANED
TOWARD THE HIGHER GUIDANCE POPS. THE COOLER HIGH TEMPERATURE
GUIDANCE APPEARS BETTER BECAUSE OF EXPECTED CLOUDINESS. THE LOW
TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY THE FRONT REMAINING NEAR THE FORECAST
AREA THROUGH THE MEDIUM-RANGE PERIOD. THERE HAS BEEN INCONSISTENCY
IN THE PLACEMENT OF DEEPER MOISTURE. THE GFS ENSEMBLE MEANS AND
OPERATIONAL GFS MOS SUPPORT CHANCE POPS THROUGH THE PERIOD.
EXPECT HIGH TEMPERATURES NEAR OR A LITTLE BELOW CLIMATOLOGY.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
A WEAK SHORTWAVE CONTINUES TO MAINTAIN AN AREA OF SHOWERS WITH A FEW
EMBEDDED THUNDERSTORMS CURRENTLY OVER NORTHERN GA MOVING EASTWARD.
SOME OF THE SHOWERS MAY MOVE OVER AGS/DNL. AFTER ANY MORNING
RESTRICTIONS...VFR EXPECTED MONDAY OUTSIDE OF ANY CONVECTION. A
DEEPENING UPPER TROUGH AND INCREASING ATMOSPHERIC MOISTURE IS
EXPECTED TO LEAD TO SCATTERED THUNDERSTORMS MONDAY
AFTERNOON...MAINLY AFTER 18Z. HAVE MENTION SHRA AFTER 21Z AT ALL
TAF SITES BUT TSRA MAY BE POSSIBLE AS WELL. WILL CONTINUE MENTION
OF SHRA IN THE TAFS TOWARDS THE END OF THE TAF PERIOD AS A SLOW-
MOVING COLD FRONT APPROACHES FROM THE OH RIVER VALLEY.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 170843
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
443 AM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EDT MONDAY...SCATTERED SHOWER ACTIVITY CONTINUES ACROSS
PORTIONS OF THE NORTH AND SOUTH CAROLINA PIEDMONTS. EXPECTING THIS
ACTIVITY TO CONTINUE MOVING EASTWARD THROUGHOUT THE MORNING.
ELSEWHERE...MORE SHOWERS WILL BE MOVING IN FROM THE WEST AND
INCREASING IN COVERAGE LATER IN THE MORNING. THEREFORE...UPDATED
NEAR TERM POPS TO REFLECT RECENT RADAR TRENDS AND ADJUSTED
TEMPERATURES ACCORDING TO RECENT OBSERVATIONS. OTHERWISE...NO OTHER
CHANGES WERE MADE.
PREVIOUS DISCUSSION...
AS OF 250 AM EDT MONDAY...CURRENT RADAR TRENDS INDICATE A LARGE
SHIELD OF STRATIFORM PRECIPITATION LOCATED ACROSS NORTHEAST GEORGIA
AND THE WESTERN UPSTATE REGION OF SOUTH CAROLINA. OTHERWISE...BROAD
CYCLONIC FLOW WILL PROMOTE CONTINUED SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE PERIOD. SHORT RANGE MODEL GUIDANCE INDICATES A
SERIES OF MID-UPPER LEVEL VORTICITY MAXIMA PASSING THROUGH THE
REGION OVER THE NEXT 18-24 HOURS. IN RESPONSE...A MILDLY UNSTABLE
AIRMASS AT THE SURFACE WILL PROVIDE ENOUGH LOW LEVEL LIFTING
POTENTIAL FOR SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT MONDAY
MORNING. SOUNDINGS INDICATE SBCAPE VALUES GENERALLY RANGING FROM
500-1000 J/KG WITH THE HIGHEST VALUES LYING ACROSS WESTERN NORTH
CAROLINA DUE TO CURRENT SHOWER ACTIVITY WORKING OVER THE ATMOSPHERE
ACROSS THE UPSTATE AND NORTHEAST GEORGIA. BY LATE MORNING TO EARLY
AFTERNOON...EXPECTING SKY COVER TO INCREASE AS THE COLUMN MOISTENS
THEREBY DECREASING SURFACE HEATING. WITH THAT...MOST IF NOT ALL
ISOLATED THUNDERSTORM DEVELOPMENT WILL CEASE LEADING TO MORE OF A
STRATIFORM PRECIPITATION REGIME WITH EMBEDDED CLUSTERS OF HEAVIER
RAINFALL. SHOWER ACTIVITY WILL DECREASE FROM NORTH TO SOUTH AS
UPPER LEVEL IMPULSES EXIT THE REGION ON MONDAY EVENING. THE
OVERNIGHT HOURS OF TUESDAY MORNING SHOULD REMAIN MOSTLY DRY AS MODEL
GUIDANCE INDICATES A LULL IN THE SHOWER ACTIVITY. TEMPERATURES
THROUGH THIS PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE NORMAL FOR LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AT 315 AM EDT MON...A CLIPPER WAVE MOVING SE THROUGH THE MIDWEST ON
TUE WILL SHARPEN UP AN ERN TROUGH AXIS OVER THE APPALACHIANS TUE
NIGHT THROUGH WED. THE NUMERICAL MODELS ALL FEATURE WEAK SFC WAVES
AHEAD OF THE UPPER CLIPPER MOVING EAST ALONG THE LINGERING WEAK
BOUNDARY IN PLACE OVER THE FORECAST AREA. IN ADDITION...THE
STRONGEST RIGHT ENTRANCE REGION UPPER JET DIVERGENCE WILL CROSS THE
FORECAST AREA MAINLY TUE NIGHT INTO WED. THESE VARIOUS FORCING
MECHANISMS WILL COINCIDE WITH A ZONE OF RELATIVELY DEEP MOISTURE
ORIENTED W TO E ACROSS THE AREA TUE THROUGH MUCH OF WED. THIS WILL
REQUIRE SOLID CHC TO LOW END LIKELY POPS THROUGHOUT. THERE IS VERY
LIMITED SHEAR IN THE MODEL PROFILES TUE THROUGH WED...AND SFC BASED
INSTABILITY MAY ALSO BE LIMITED DESPITE THE HIGH DEWPOINTS BECAUSE
OF CLOUD COVER. LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREAT.
WILL CONTINUE TO FEATURE A SMALLER THAN CLIMO DIURNAL RANGE OF WARM
MIN TEMPS AND COOLER THAN NORMAL MAX TEMPS TUE THROUGH WED NIGHT
GIVEN THE CLOUD COVER AND PRECIP CHANCES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 320 AM EDT MONDAY...HEIGHTS WILL BUILD FROM THE W THU THROUGH
FRI AS A LARGE ANTICYCLONE TAKES UP RESIDENCE OVER THE SRN PLAINS.
HOWEVER...ENERGY TOPPING THE RIDGE COULD SPARK MCS ACITIVTY THAT MAY
MAKE A RUN TOWARD THE SRN APPALACHIANS LATE FRI/FRI NIGHT. THIS IS
QUITE UNCERTAIN AT PRESENT...SO WILL KEEP THE THUNDERSTORM FORECAST
ON A MORE TYPICAL SCATTERED DIURNAL PATTERN THU AND FRI AFTNS.
UPPER RIDGING WILL BECOME MORE DOMINANT THROUGH THE WEEKEND.
HOWEVER...LINGERING LOW LEVEL MOISTURE AND A SE ATLANTIC FETCH COULD
LEAD TO MORNING STRATUS EACH DAY. THERE WILL PERSIST A MAINLY
DIURNAL ISOLD TO SCT THUNDERSTORM THREAT...ESPECIALLY OVER THE MTNS.
MAXES WILL STEADILY RISE TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES BY
SUNDAY AFTN.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH
THE ONLY EXCEPTIONS BEING LOWERING VISB ADJACENT TO ANY THUNDERSTORM
DEVELOPMENT ON MONDAY AFTERNOON. IN THE NEAR TERM...DECIDED TO PULL
THE PREVIOUS SHRA TEMPO AS LATEST RADAR TRENDS SHOW A GRADUAL DECAY
IN ACTIVITY WELL TO THE WEST. EXPECTING CIGS TO LOWER TO AROUND
10KFT AS UPPER SHORTWAVE TROF PASSES THROUGH TOMORROW MORNING.
LIKEWISE...A GRADUAL INCREASE IN COVERAGE OF SHOWER ACTIVITY IS
EXPECTED THUS PROMPTING MENTION OF -SHRA AROUND 15Z. AS SOME
HEATING OCCURS DURING THE EARLY AFTERNOON HOURS...THERE WILL BE A
CHANCE FOR SOME RATHER DISORGANIZED CONVECTION LEADING TO PROB30 FOR
TSRA THROUGH THE AFTERNOON. SOME LOWER BKN CIGS ARE POSSIBLE LATE
IN THE PERIOD DUE TO OVERSPREADING CONVECTIVE DEBRIS. WINDS WILL
GENERALLY BE LIGHT AND SOUTHERLY.
ELSEWHERE...LOOK FOR VFR CONDITIONS TO PERSIST THROUGH THE TAF
PERIOD ASIDE FOR VISB RESTRICTIONS DUE TO THUNDERSTORM DEVELOPMENT
MONDAY AFTERNOON. AS WITH KCLT ABOVE...EXPECTING COVERAGE OF
SHOWERS TO INCREASE THROUGH THE MORNING HOURS IN RESPONSE TO UPPER
TROF. MODELS INDICATE THE BEST INSTABILITY TO BE AROUND THE 15-18Z
TIMEFRAME ACROSS THE FOOTHILLS OF NORTH CAROLINA...AND THE
UPSTATE/PIEDMONT REGIONS OF SOUTH CAROLINA. THUS...WENT WITH TEMPO
GROUPS FOR TSRA AT ALL CORRESPONDING SITES FOR THIS PERIOD. BEYOND
THAT... EXPECTING LESS THUNDERSTORM PERSISTENCE THUS REVERTED TO
-SHRA WITH VCTS MENTION IN THE TAFS. SHOWER ACTIVITY WILL TAPER OFF
FROM NORTH TO SOUTH MONDAY EVENING THEREFORE KEPT VCSH AT ALL SOUTH
CAROLINA SITES.
OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 100% HIGH 100% HIGH 94% MED 73%
KGSP HIGH 100% HIGH 100% HIGH 94% MED 73%
KAVL HIGH 91% HIGH 100% HIGH 94% HIGH 83%
KHKY HIGH 100% HIGH 100% HIGH 94% MED 73%
KGMU HIGH 100% HIGH 100% HIGH 94% MED 73%
KAND HIGH 97% HIGH 100% HIGH 94% MED 73%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG
SHORT TERM...HG
LONG TERM...HG
AVIATION...CDG
000
FXUS62 KCAE 170824
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
424 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MID-LEVEL SHORTWAVE TROUGH APPROACHING THE FORECAST AREA THIS
MORNING HAS REMOVED THE CAPPING THAT HAS BEEN DOMINATE DURING THE
PAST FEW DAYS. MOISTURE HAS INCREASED AHEAD OF THE DIFFUSE FRONT
DROPPING SOUTHWARD AND TOWARD THE FORECAST AREA. BELIEVE THE
SHOWERS IN UPSTATE SOUTH CAROLINA AND GEORGIA EARLY THIS MORNING
ARE MAINLY ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH. THE
HIGH-RESOLUTION MODELS SHOW COVERAGE DIMINISHING AS THESE SHOWERS
MOVE INTO THE FORECAST AREA THIS MORNING. THEREFORE...WE DID NOT
FORECAST CATEGORICAL POPS. GENERALLY FORECASTED POPS OF 50 TO 70
PERCENT WITH THE HIGHEST POPS FOR NOW IN THE SOUTHWEST PART BASED ON
RADAR TRENDS. THE NAM AND GFS SHOW PRECIPITABLE WATER AROUND 2
INCHES THIS AFTERNOON. THE HIGH MOISTURE AND HEATING SHOULD HELP
SUPPORT THUNDERSTORMS BUT COVERAGE MAY BE LIMITED BECAUSE LIFT
ASSOCIATED THIS MORNING/S SHORTWAVE TROUGH SHOULD BE EAST OF THE
FORECAST AREA. THE HIGH RESOLUTION MODELS INDICATE SCATTERED
COVERAGE. CLOUDINESS SHOULD LIMIT INSTABILITY TODAY. THE NAM
DISPLAYS SURFACE-BASED LI/S -4 TO -5 TODAY. THE THREAT OF SEVERE
THUNDERSTORMS APPEARS LOW BECAUSE OF THE LIMITED INSTABILITY. AN
AVERAGE OF THE NAM AND GFS PLUS THE SREF MEAN SUPPORT GENERAL RAIN
AMOUNTS NEAR ONE-HALF OF AN INCH. HEAVY RAIN MAY OCCUR BECAUSE OF
THE HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING. LEANED TOWARD
THE COOLER TEMPERATURE GUIDANCE TODAY BECAUSE OF CLOUDINESS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
HIGH MOISTURE ASSOCIATED WITH THE DIFFUSE EAST-WEST ORIENTED FRONT
WILL CONTINUE. THE MODELS KEEP BROAD UPPER-LEVEL TROUGHING WITH A
SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS. LEANED
TOWARD THE HIGHER GUIDANCE POPS. THE COOLER HIGH TEMPERATURE
GUIDANCE APPEARS BETTER BECAUSE OF EXPECTED CLOUDINESS. THE LOW
TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY THE FRONT REMAINING NEAR THE FORECAST
AREA THROUGH THE MEDIUM-RANGE PERIOD. THERE HAS BEEN INCONSISTENCY
IN THE PLACEMENT OF DEEPER MOISTURE. THE GFS ENSEMBLE MEANS AND
OPERATIONAL GFS MOS SUPPORT CHANCE POPS THROUGH THE PERIOD.
EXPECT HIGH TEMPERATURES NEAR OR A LITTLE BELOW CLIMATOLOGY.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
A BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS CURRENTLY OVER UPSTATE
SC MOVING EAST. AN UPPER DISTURBANCE WILL ALLOW SOME OF THIS
ACTIVITY TO CONTINUE TO MOVE EASTWARD DURING THE REMAINDER OF THE
EARLY MORNING HOURS. SOME OF THE SHOWERS MAY MOVE OVER AGS/DNL BUT
WILL NOT INCLUDE IN THOSE TAFS FOR NOW SINCE THE BAND OF
PRECIPITATION APPEARS TO BE WEAKENING AS IT MOVES EAST. LATEST CAE
VAD WIND PROFILE INDICATING SW WINDS AROUND 25 KNOTS AT 2000 FEET.
NAM BUFKIT INDICATING DEEPEST MOISTURE AROUND 3000-4000 FEET
OVERNIGHT SO HAVE INCLUDED TEMPO GROUP BEFORE SUNRISE FOR SOME MVFR
CIGS. THESE FACTORS ALONG WITH SOME MID/HIGH LEVEL CONVECTIVE DEBRIS
CLOUDINESS WOULD WORK AGAINST FOG FORMATION. AFTER ANY MORNING
RESTRICTIONS...VFR EXPECTED MONDAY OUTSIDE OF ANY CONVECTION. A
DEEPENING UPPER TROUGH AND INCREASING ATMOSPHERIC MOISTURE IS
EXPECTED TO LEAD TO SCATTERED THUNDERSTORMS MONDAY
AFTERNOON...MAINLY AFTER 18Z. HAVE MENTION SHRA AFTER 21Z AT ALL TAF
SITES BUT TSRA MAY BE POSSIBLE AS WELL. WILL CONTINUE MENTION OF
SHRA IN THE TAFS TOWARDS THE END OF THE TAF PERIOD AS A SLOW-MOVING
COLD FRONT APPROACHES FROM THE OH RIVER VALLEY.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 170822
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
422 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MID-LEVEL SHORTWAVE TROUGH APPROACHING THE FORECAST AREA THIS
MORNING HAS REMOVED THE CAPPING THAT HAS BEEN DOMINATE DURING THE
PAST FEW DAYS. MOISTURE HAS INCREASED AHEAD OF THE DIFFUSE FRONT
DROPPING SOUTHWARD AND TOWARD THE FORECAST AREA. BELIEVE THE
SHOWERS IN UPSTATE SOUTH CAROLINA AND GEORGIA EARLY THIS MORNING
ARE MAINLY ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH. THE
HIGH-RESOLUTION MODELS SHOW COVERAGE DIMINISHING AS THESE SHOWERS
MOVE INTO THE FORECAST AREA THIS MORNING. THEREFORE...WE DID NOT
FORECAST CATEGORICAL POPS. GENERALLY FORECASTED POPS OF 50 TO 70
PERCENT WITH THE HIGHEST POPS FOR NOW IN THE SOUTH PART BASED ON
RADAR TRENDS. THE NAM AND GFS SHOW PRECIPITABLE WATER AROUND 2
INCHES THIS AFTERNOON. THE HIGH MOISTURE AND HEATING SHOULD HELP
SUPPORT THUNDERSTORMS BUT COVERAGE MAY BE LIMITED BECAUSE LIFT
ASSOCIATED THIS MORNING/S SHORTWAVE TROUGH SHOULD BE EAST OF THE
FORECAST AREA. THE HIGH RESOLUTION MODELS INDICATE SCATTERED
COVERAGE. CLOUDINESS SHOULD LIMIT INSTABILITY TODAY. THE NAM
DISPLAYS SURFACE-BASED LI/S -4 TO -5 TODAY. THE THREAT OF SEVERE
THUNDERSTORMS APPEARS LOW BECAUSE OF THE LIMITED INSTABILITY. AN
AVERAGE OF THE NAM AND GFS PLUS THE SREF MEAN SUPPORT GENERAL RAIN
AMOUNTS NEAR ONE-HALF OF AN INCH. HEAVY RAIN MAY OCCUR BECAUSE OF
THE HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING. LEANED TOWARD
THE COOLER TEMPERATURE GUIDANCE TODAY BECAUSE OF CLOUDINESS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
HIGH MOISTURE ASSOCIATED WITH THE DIFFUSE EAST-WEST ORIENTED FRONT
WILL CONTINUE. THE MODELS KEEP BROAD UPPER-LEVEL TROUGHING WITH A
SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS. LEANED
TOWARD THE HIGHER GUIDANCE POPS. THE COOLER HIGH TEMPERATURE
GUIDANCE APPEARS BETTER BECAUSE OF EXPECTED CLOUDINESS. THE LOW
TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY THE FRONT REMAINING NEAR THE FORECAST
AREA THROUGH THE MEDIUM-RANGE PERIOD. THERE HAS BEEN INCONSISTENCY
IN THE PLACEMENT OF DEEPER MOISTURE. THE GFS ENSEMBLE MEANS AND
OPERATIONAL GFS MOS SUPPORT CHANCE POPS THROUGH THE PERIOD.
EXPECT HIGH TEMPERATURES NEAR OR A LITTLE BELOW CLIMATOLOGY.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
A BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS CURRENTLY OVER UPSTATE
SC MOVING EAST. AN UPPER DISTURBANCE WILL ALLOW SOME OF THIS
ACTIVITY TO CONTINUE TO MOVE EASTWARD DURING THE REMAINDER OF THE
EARLY MORNING HOURS. SOME OF THE SHOWERS MAY MOVE OVER AGS/DNL BUT
WILL NOT INCLUDE IN THOSE TAFS FOR NOW SINCE THE BAND OF
PRECIPITATION APPEARS TO BE WEAKENING AS IT MOVES EAST. LATEST CAE
VAD WIND PROFILE INDICATING SW WINDS AROUND 25 KNOTS AT 2000 FEET.
NAM BUFKIT INDICATING DEEPEST MOISTURE AROUND 3000-4000 FEET
OVERNIGHT SO HAVE INCLUDED TEMPO GROUP BEFORE SUNRISE FOR SOME MVFR
CIGS. THESE FACTORS ALONG WITH SOME MID/HIGH LEVEL CONVECTIVE DEBRIS
CLOUDINESS WOULD WORK AGAINST FOG FORMATION. AFTER ANY MORNING
RESTRICTIONS...VFR EXPECTED MONDAY OUTSIDE OF ANY CONVECTION. A
DEEPENING UPPER TROUGH AND INCREASING ATMOSPHERIC MOISTURE IS
EXPECTED TO LEAD TO SCATTERED THUNDERSTORMS MONDAY
AFTERNOON...MAINLY AFTER 18Z. HAVE MENTION SHRA AFTER 21Z AT ALL TAF
SITES BUT TSRA MAY BE POSSIBLE AS WELL. WILL CONTINUE MENTION OF
SHRA IN THE TAFS TOWARDS THE END OF THE TAF PERIOD AS A SLOW-MOVING
COLD FRONT APPROACHES FROM THE OH RIVER VALLEY.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 170740
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
340 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL BUILD FROM THE NORTH INTO NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
THROUGH SUNRISE...CLOUDS HAVE BEEN SLOW TO THICKEN EARLY THIS
MORNING. TEMPERATURES ARE RUNNING A TAD COOLER THAN EXPECTED AS A
RESULT. A LARGE MASS OF SHOWERS/TSTMS MOVING ACROSS NORTHERN
GEORGIA AND THE UPPER SAVANNAH RIVER VALLEY WILL CONTINUE TO
PROPAGATE SLOWLY EAST. MOST HIGH RESOLUTION MODELS DISSIPATE THE
BULK OF THIS ACTIVITY BEFORE REACHING THE FAR WESTERN ZONES PRIOR
TO SUNRISE. WILL MAINTAIN A MENTION OF SLIGHT CHANCE POPS IN THESE
AREAS TO COVER ANY ACTIVITY THAT MAY DRIFT EAST INTO THE LOCAL
FORECAST AREA.
TODAY...IT LOOKS TO BE CONVECTIVELY ACTIVE DAY AS THE UPPER RIDGE
RAPIDLY BREAKS DOWN AND THE WESTERN FLANKS OF ATLANTIC HIGH
PRESSURE BUCKLES. FILTERED SUNSHINE THIS MORNING WILL ALLOW
TEMPERATURES TO WARM QUICKLY INTO THE UPPER 80S FOR MOST
LOCATIONS AWAY FROM THE COAST WITH MODIFIED BUFR SOUNDINGS
SUPPORTING CONVECTIVE TEMPERATURES AROUND 84-85 DEGREES. THE
PRIMARY FOCI FOR TSTMS TO DEVELOP TODAY WILL BE ALONG A SOMEWHAT
ILL-DEFINED SEA BREEZE AND A CONVECTIVE OUTFLOW BOUNDARY THAT CAN
BE SEEN EMERGING FROM THE CONVECTION OVER NORTHERN GEORGIA EARLY
THIS MORNING. THE VARIOUS LAKE BREEZE CIRCULATIONS AROUND THE
SANTEE-COOPER LAKES COULD ALSO COME INTO PLAY AS THE AFOREMENTIONED
OUTFLOW BECOMES ALIGNED SOUTHWEST-NORTHEAST ACROSS THE INTERIOR
SOUTHEAST SOUTH CAROLINA ZONES BY EARLY AFTERNOON.
THERE LOOKS TO BE A PRETTY HEALTHY COVERAGE OF SHOWERS/TSTMS
DURING PEAK HEATING SO WILL BUMP POPS UP SLIGHTLY TO 60 PERCENT
AWAY FROM THE BEACHES...WHICH WILL LINGER INTO THE EARLY EVENING
HOURS. SHEAR IS WEAK AND INSTABILITY PROGNOSTICATIONS ARE NOT ALL
THAT IMPRESSIVE SO THE RISK FOR SEVERE WEATHER LOOKS TO BE PRETTY
LOW...HOWEVER AN ISOLATED WET MICROBURST OR TWO CAN NOT BE
COMPLETELY RULED OUT WHERE UPDRAFTS BECOME ENHANCED BY MESOSCALE
BOUNDARY INTERACTIONS. SHOWER/TSTMS ACTIVITY IS EXPECTED TO SLOWLY
FORM/REFORM ACROSS INTERIOR SOUTHEAST GEORGIA BY LATE AFTERNOON...
POSSIBLY BECOMING ENHANCED BY ADDITIONAL CONVECTIVE OUTFLOW.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
TONIGHT...SHOWER/TSTMS ACTIVITY WILL GRADUALLY WIND DOWN AS
INSTABILITY WANES WITH THE LOSS OF INSOLATION AND THE ATMOSPHERE
IS STEADILY OVERTURNED. THERE ARE SOME INDICATIONS THAT
CONVECTION COULD CLUSTER ALONG/NEAR THE ALTAMAHA RIVER EARLY THIS
EVENING AS THE GULF SEA BREEZE MAKES A RUN FOR THE FAR SOUTHERN
ZONES...BUT IT IS UNCLEAR WHETHER THE GULF SEA BREEZE WILL MAKE
IT THIS FAR NORTH. THIS WILL HAVE TO THE WATCHED CAREFULLY. WILL
CARRY 40-60 PERCENT POPS EARLY THIS EVENING...DIMINISHING TO 20-30
PERCENT FORTH OVERNIGHT HOURS. LOWS WILL RANGE FROM AROUND 70 WELL
INLAND TO THE MID 70S AT THE COAST.
TUESDAY...A PROGRESSIVE NEARLY ZONAL PATTERN ALOFT WILL ALLOW A
SERIES OF WEAK SHORTWAVES TO CONTINUALLY MOVE THROUGH THE SOUTHEAST
STATES EARLY IN THE WEEK. AT THE SURFACE...A WAVE OF LOW PRESSURE
WILL DEVELOP ALONG A COLD FRONT STRETCHING FROM APPROXIMATELY
UPSTATE SOUTH CAROLINA THROUGH COASTAL NORTH CAROLINA. THE
COMBINATION OF UPPER LEVEL ENERGY AND DEEP LAYER MOISTURE...ALONG
WITH FRONTAL CONVERGENCE...WILL SUPPORT INCREASING CONVECTIVE
COVERAGE BY TUESDAY AFTERNOON. THE BEST POTENTIAL FOR THUNDERSTORM
ACTIVITY WILL BE ALONG THE FAR INLAND TIER COUNTIES CLOSEST TO THE
LINGERING FRONT...YET SOLID DEEP WESTERLY FLOW SHOULD STILL PUSH
UPSTREAM CONVECTION TOWARD THE COAST. WILL THUS ADVERTISE
THUNDERSTORM CHANCES RANGING FROM 50 TO 60 PERCENT INLAND TO 40
PERCENT CLOSER TO THE COAST DURING THE DAYTIME HOURS. IF THE
CENTER OF THE MAIN SURFACE WAVE SLIPS TOWARD THE OUTER BANKS OF
NORTH CAROLINA LATE TUESDAY NIGHT...THEN SHOWER/THUNDERSTORM
COVERAGE WILL DECREASE FROM SOUTH TO NORTH AFTER MIDNIGHT.
SUFFICIENT SYNOPTIC SCALE FORCING WILL STILL MAINTAIN CHANCES IN
THE 20 PERCENT RANGE SOUTHEAST GEORGIA TO THE 30 TO 40 PERCENT
RANGE CHARLESTON TRI COUNTY REGION TOWARD THE PRE DAWN HOURS. HIGH
TEMPERATURES WILL REACH THE UPPER 80S TO AROUND 90 DEGREES AWAY
FROM THE LOCALLY COOLER COASTLINE.
WEDNESDAY...CONVECTIVE COVERAGE WILL SURGE AGAIN AFTER
DAYBREAK...AS THE AMPLIFYING SHORTWAVE TROUGH MOVING OVER THE EAST
COAST PULLS THE FRONT DIRECTLY INTO THE FORECAST AREA DURING THE
AFTERNOON HOURS. HAVE INDICATED HIGHEST THUNDERSTORM POTENTIAL OF
THE PERIOD ON WEDNESDAY...WITH LIKELY POPS FOR THE MAJORITY OF
THE ZONES AWAY FROM THE COASTLINE. THE AXIS OF THE LOW PRESSURE
WAVE WILL SHIFT INTO THE MARINE ZONES WITH THE MAIN SHORTWAVE
OVERNIGHT...PULLING DEEPEST MOISTURE AND ASSOCIATED CONVECTIVE
ACTIVITY TOWARD THE EASTERN HALF OF THE FORECAST AREA AND THE
COASTAL WATERS. HIGH TEMPERATURES ON WEDNESDAY WILL BE A BIT
TRICKY...ESPECIALLY ACROSS NORTHERN AREAS THAT COULD END UP ON THE
COOL SIDE OF THE DESCENDING FRONT. WILL INDICATE MID TO UPPER 80S
NORTHERN MOST ZONES AND UPPER 80S TO AROUND 90 FARTHER SOUTH.
THURSDAY...THE WEAK COLD FRONT WILL CONTINUE TO SLIP SOUTH THROUGH
THE FORECAST AREA EARLY IN THE DAY...BEFORE STALLING ALONG THE
SOUTHERN PERIPHERY AS IT BECOMES MORE PARALLEL TO FLOW ALOFT.
THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND ECMWF MODEL
SOLUTIONS REGARDING PRECIPITATION COVERAGE...A RESULT OF THE GFS
MAINTAINING A MORE PROMINENT UPPER TROUGH OVER THE SOUTHEAST
STATES. HAVE OPTED TO MAINTAIN SOLID THUNDERSTORM CHANCES ACROSS
THE AREA FOR THE AFTERNOON PERIOD...INDICATING SLIGHTLY HIGHER
POTENTIAL ACROSS THE SOUTHERN SECTIONS CLOSEST TO THE STALLED
BOUNDARY. HIGH TEMPERATURES COULD ONCE AGAIN REFLECT A SLIGHT
NORTHEAST/SOUTHWEST GRADIENT...WITH SUBTLE COOLER CONDITIONS IN
THE MID TO UPPER 80S CHARLESTON TRI COUNTY REGION COMPARED TO
AROUND 90 DEGREES FARTHER SOUTH NEAR THE ALTAMAHA RIVER.
OVERALL SEVERE POTENTIAL LOOKS LOW THROUGH THE PERIOD...AS THE
STRONGEST SYNOPTIC FORCING AND WIND FIELDS REMAIN NORTH OF THE
FORECAST AREA. HOWEVER...AS IS TYPICAL THIS TIME OF YEAR...AN
ISOLATED STRONG TO SEVERE THUNDERSTORM IS POSSIBLE WHERE BOUNDARY
INTERACTIONS OCCUR AND ENHANCE UPDRAFT STRENGTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE CENTER OF UPPER LEVEL RIDGING WILL REMAIN WEST OF THE
REGION...ALLOWING THE PATTERN ALOFT FOR THE SOUTHEAST STATES TO
BE SOMEWHAT WEAK AND PROGRESSIVE THROUGH MUCH OF THE EXTENDED
PERIOD. THE LINGERING FRONT NEAR THE SOUTHERN PERIPHERY OF THE
FORECAST AREA LOOKS TO REMAIN GENERALLY IN PLACE...EVENTUALLY
TRANSITIONING INTO A COASTAL FRONT/COASTAL TROUGH FEATURE AS HIGH
PRESSURE BUILDS FROM THE NORTH. MEDIUM RANGE MODEL SOLUTIONS STILL
DIVERGE ON DETAILS FOR THE LATE WEEK AND WEEKEND PERIOD...AND HAVE
DECIDED TO MAINTAIN A RATHER GENERIC 30 PERCENT POP DURING THE
DAYTIME HOURS FRIDAY THROUGH AT LEAST SUNDAY. IF THE COASTAL
TROUGH PATTERN DOES INDEED TAKE SHAPE...THEN EXPECT BEST
CONVECTIVE COVERAGE TO TRANSITION OFFSHORE EACH NIGHT. HIGH
TEMPERATURES WILL VARY LITTLE EACH AFTERNOON...REACHING THE UPPER
80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
GENERALLY VFR. RISK FOR SHOWERS/TSTMS WILL INCREASE LATER THIS
MORNING AND INTO THE AFTERNOON. MODELS GENERALLY FAVOR THE
CORRIDOR OF GREATEST COVERAGE REMAINING TO THE WEST OF THE KCHS-
KSAV CORRIDOR...ALTHOUGH SOME OF THE HIGHER RESOLUTION DATA
SUGGEST KCHS MAY HAVE A BETTER SHOW LATER THIS AFTERNOON FOR
IMPACTS. WILL TEMPO 19-21Z FOR 4SM TSRA BR SCT015 BKN035CB TO
COVER FOR NOW. WILL LEAVE TSRA OUT OF THE KSAV TAF UNTIL CONFIDENCE
INCREASES. AMENDMENTS WILL MOST CERTAINLY BE NEEDED THROUGHOUT
THE DAY AS MESOSCALE AND SHORT TERM RADAR TRENDS BECOME MORE
APPARENT.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS MONDAY NIGHT
THROUGH THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA.
&&
.MARINE...
TODAY...SOUTHERLY WIND REGIME WILL PERSIST WITH WINDS GENERALLY 10
KT OR LESS AND SEAS 2-4 FT.
TONIGHT...WINDS WILL INCREASE SLIGHTLY AHEAD OF AN APPROACHING
COLD FRONT. SPEEDS COULD REACH AS HIGH AS 15-20 KT AT TIMES WITH
SEAS 2-4 FT. SMALL CRAFT ADVISORY CONDITIONS ARE UNLIKELY AT THIS
TIME.
TUESDAY THROUGH FRIDAY...THE MARINE ZONES WILL BECOME SITUATED
BETWEEN AN APPROACHING COLD FRONT/SURFACE TROUGH INLAND AND
RETREATING HIGH PRESSURE TO THE EAST EARLY THIS WEEK. SOUTHERLY
FLOW WILL SURGE SLIGHTLY BY WEDNESDAY AS THE PRESSURE GRADIENT
TIGHTENS BETWEEN THE TWO FEATURES...SUPPORTING A BRIEF PERIOD OF
15 TO 20 KT WINDS AND SEAS UP TO 5 FT BEYOND 20 NM. EXPECT WIND
DIRECTIONS TO VEER WEST/NORTHWEST AS THE FRONT STEADILY SLIPS INTO
THE FORECAST AREA THURSDAY...AS SPEEDS DIMINISH A BIT WITHIN A
WEAKENING PRESSURE GRADIENT. NUMERICAL MODEL SOLUTIONS DIFFER
REGARDING THE PRECISE LOCATION OF THE STALLING FRONT BY LATE
WEEK...AND WILL LEAN TOWARD PERSISTENCE IN INDICATING A GENERAL
EAST/NORTHEAST FLOW FOR THURSDAY AND FRIDAY. WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY CONDITIONS THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/WMS
000
FXUS62 KGSP 170726
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
326 AM EDT MON JUN 17 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 250 AM EDT MONDAY...CURRENT RADAR TRENDS INDICATE A LARGE
SHIELD OF STRATIFORM PRECIPITATION LOCATED ACROSS NORTHEAST GEORGIA
AND THE WESTERN UPSTATE REGION OF SOUTH CAROLINA. OTHERWISE...BROAD
CYCLONIC FLOW WILL PROMOTE CONTINUED SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE PERIOD. SHORT RANGE MODEL GUIDANCE INDICATES A
SERIES OF MID-UPPER LEVEL VORTICITY MAXIMA PASSING THROUGH THE
REGION OVER THE NEXT 18-24 HOURS. IN RESPONSE...A MILDLY UNSTABLE
AIRMASS AT THE SURFACE WILL PROVIDE ENOUGH LOW LEVEL LIFTING
POTENTIAL FOR SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT MONDAY
MORNING. SOUNDINGS INDICATE SBCAPE VALUES GENERALLY RANGING FROM
500-1000 J/KG WITH THE HIGHEST VALUES LYING ACROSS WESTERN NORTH
CAROLINA DUE TO CURRENT SHOWER ACTIVITY WORKING OVER THE ATMOSPHERE
ACROSS THE UPSTATE AND NORTHEAST GEORGIA. BY LATE MORNING TO EARLY
AFTERNOON...EXPECTING SKY COVER TO INCREASE AS THE COLUMN MOISTENS
THEREBY DECREASING SURFACE HEATING. WITH THAT...MOST IF NOT ALL
ISOLATED THUNDERSTORM DEVELOPMENT WILL CEASE LEADING TO MORE OF A
STRATIFORM PRECIPITATION REGIME WITH EMBEDDED CLUSTERS OF HEAVIER
RAINFALL. SHOWER ACTIVITY WILL DECREASE FROM NORTH TO SOUTH AS
UPPER LEVEL IMPULSES EXIT THE REGION ON MONDAY EVENING. THE
OVERNIGHT HOURS OF TUESDAY MORNING SHOULD REMAIN MOSTLY DRY AS MODEL
GUIDANCE INDICATES A LULL IN THE SHOWER ACTIVITY. TEMPERATURES
THROUGH THIS PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE NORMAL FOR LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AT 315 AM EDT MON...A CLIPPER WAVE MOVING SE THROUGH THE MIDWEST ON
TUE WILL SHARPEN UP AN ERN TROUGH AXIS OVER THE APPALACHIANS TUE
NIGHT THROUGH WED. THE NUMERICAL MODELS ALL FEATURE WEAK SFC WAVES
AHEAD OF THE UPPER CLIPPER MOVING EAST ALONG THE LINGERING WEAK
BOUNDARY IN PLACE OVER THE FORECAST AREA. IN ADDITION...THE
STRONGEST RIGHT ENTRANCE REGION UPPER JET DIVERGENCE WILL CROSS THE
FORECAST AREA MAINLY TUE NIGHT INTO WED. THESE VARIOUS FORCING
MECHANISMS WILL COINCIDE WITH A ZONE OF RELATIVELY DEEP MOISTURE
ORIENTED W TO E ACROSS THE AREA TUE THROUGH MUCH OF WED. THIS WILL
REQUIRE SOLID CHC TO LOW END LIKELY POPS THROUGHOUT. THERE IS VERY
LIMITED SHEAR IN THE MODEL PROFILES TUE THROUGH WED...AND SFC BASED
INSTABILITY MAY ALSO BE LIMITED DESPITE THE HIGH DEWPOINTS BECAUSE
OF CLOUD COVER. LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREAT.
WILL CONTINUE TO FEATURE A SMALLER THAN CLIMO DIURNAL RANGE OF WARM
MIN TEMPS AND COOLER THAN NORMAL MAX TEMPS TUE THROUGH WED NIGHT
GIVEN THE CLOUD COVER AND PRECIP CHANCES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 320 AM EDT MONDAY...HEIGHTS WILL BUILD FROM THE W THU THROUGH
FRI AS A LARGE ANTICYCLONE TAKES UP RESIDENCE OVER THE SRN PLAINS.
HOWEVER...ENERGY TOPPING THE RIDGE COULD SPARK MCS ACITIVTY THAT MAY
MAKE A RUN TOWARD THE SRN APPALACHIANS LATE FRI/FRI NIGHT. THIS IS
QUITE UNCERTAIN AT PRESENT...SO WILL KEEP THE THUNDERSTORM FORECAST
ON A MORE TYPICAL SCATTERED DIURNAL PATTERN THU AND FRI AFTNS.
UPPER RIDGING WILL BECOME MORE DOMINANT THROUGH THE WEEKEND.
HOWEVER...LINGERING LOW LEVEL MOISTURE AND A SE ATLANTIC FETCH COULD
LEAD TO MORNING STRATUS EACH DAY. THERE WILL PERSIST A MAINLY
DIURNAL ISOLD TO SCT THUNDERSTORM THREAT...ESPECIALLY OVER THE MTNS.
MAXES WILL STEADILY RISE TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES BY
SUNDAY AFTN.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH
THE ONLY EXCEPTIONS BEING LOWERING VISB ADJACENT TO ANY THUNDERSTORM
DEVELOPMENT ON MONDAY AFTERNOON. IN THE NEAR TERM...DECIDED TO PULL
THE PREVIOUS SHRA TEMPO AS LATEST RADAR TRENDS SHOW A GRADUAL DECAY
IN ACTIVITY WELL TO THE WEST. EXPECTING CIGS TO LOWER TO AROUND
10KFT AS UPPER SHORTWAVE TROF PASSES THROUGH TOMORROW MORNING.
LIKEWISE...A GRADUAL INCREASE IN COVERAGE OF SHOWER ACTIVITY IS
EXPECTED THUS PROMPTING MENTION OF -SHRA AROUND 15Z. AS SOME
HEATING OCCURS DURING THE EARLY AFTERNOON HOURS...THERE WILL BE A
CHANCE FOR SOME RATHER DISORGANIZED CONVECTION LEADING TO PROB30 FOR
TSRA THROUGH THE AFTERNOON. SOME LOWER BKN CIGS ARE POSSIBLE LATE
IN THE PERIOD DUE TO OVERSPREADING CONVECTIVE DEBRIS. WINDS WILL
GENERALLY BE LIGHT AND SOUTHERLY.
ELSEWHERE...LOOK FOR VFR CONDITIONS TO PERSIST THROUGH THE TAF
PERIOD ASIDE FOR VISB RESTRICTIONS DUE TO THUNDERSTORM DEVELOPMENT
MONDAY AFTERNOON. AS WITH KCLT ABOVE...EXPECTING COVERAGE OF
SHOWERS TO INCREASE THROUGH THE MORNING HOURS IN RESPONSE TO UPPER
TROF. MODELS INDICATE THE BEST INSTABILITY TO BE AROUND THE 15-18Z
TIMEFRAME ACROSS THE FOOTHILLS OF NORTH CAROLINA...AND THE
UPSTATE/PIEDMONT REGIONS OF SOUTH CAROLINA. THUS...WENT WITH TEMPO
GROUPS FOR TSRA AT ALL CORRESPONDING SITES FOR THIS PERIOD. BEYOND
THAT... EXPECTING LESS THUNDERSTORM PERSISTENCE THUS REVERTED TO
-SHRA WITH VCTS MENTION IN THE TAFS. SHOWER ACTIVITY WILL TAPER OFF
FROM NORTH TO SOUTH MONDAY EVENING THEREFORE KEPT VCSH AT ALL SOUTH
CAROLINA SITES.
OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.
CONFIDENCE TABLE...
07-13Z 13-19Z 19-01Z 01-07Z
KCLT HIGH 100% HIGH 100% HIGH 100% MED 69%
KGSP HIGH 100% HIGH 100% HIGH 100% MED 69%
KAVL HIGH 94% HIGH 97% HIGH 100% MED 78%
KHKY HIGH 100% HIGH 100% HIGH 100% MED 69%
KGMU HIGH 100% HIGH 100% HIGH 100% MED 69%
KAND HIGH 100% HIGH 100% HIGH 100% MED 69%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...CDG
SHORT TERM...HG
LONG TERM...HG
AVIATION...CDG
000
FXUS62 KGSP 170554
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
154 AM EDT MON JUN 17 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY CROSS THE OHIO VALLEY TO START THE WEEK AS
A SOUTHWESTERLY FLOW BRINGS MOISTURE FROM THE GULF. EXPECT THE FRONT
TO STALL FROM WEST TO EAST JUST SOUTH OF OUR REGION AND SLOWLY
DISSIPATE IN THE SECOND HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
1000 PM UPDATE...CLUSTERS OF SHOWERS/TSTMS CONTINUE TO MOVE THRU
EAST TN AND NRN GA UNDER BROADLY CYCLONIC UPPER FLOW. SPC
MESOANALYSIS SHOWS WELL OVER 1000 J/KG OF MUCAPE ACROSS THAT AREA
DIMINISHING TO 500-1000 J OVER THE ERN HALF OF OUR CWFA. LLVL WINDS
NOT IMPRESSIVE BUT SEEM TO BE ENOUGH TO CONTINUE TO SUPPLY MOISTURE
TO THE CELLS. COMPOSITE REFLECTIVITY TRENDS SUGGEST TSTMS ARE
BEGINNING TO STRUGGLE AS INSTABILITY BEGINS TO WEAKEN...AND STRONGER
PORTIONS OF THE COMPLEX OVER NRN GA SEEM TO BE PROPAGATING SOUTH
TOWARD BETTER MOISTURE. REFOCUSED POPS TOWARD THE UPSTATE THIS
EVENING AS THIS AREA HAS A BETTER CHANCE OF SEEING PRECIP...SINCE
CELLS OVER EAST TN ARE ON A SLIGHTLY MORE NORTHERLY TRACK AND MAY
NOT PUSH INTO THE SPINE OF THE APPALACHIANS BEFORE RUNNING OUT OF
STEAM. SOME REDEVELOPMENT STILL POSSIBLE OVERNIGHT OVER OUR AREA SO
MAINTAINED CHC POPS FOLLOWING THE EVENING PEAK.
700 PM UPDATE...WITH THE WINDOW FOR DIURNAL CONVECTION TO DEVELOP IN
PLACE CLOSED...THE CWFA IS LIKELY TO REMAIN PRACTICALLY RAIN FREE
UNTIL THE FORCING FROM THE UPSTREAM SHORTWAVE ARRIVES LATER THIS
EVENING. ACTIVITY ASSOCIATED WITH THAT FEATURE OVER SRN MIDDLE TENN
AND NRN ALABAMA IS GOING FAIRLY WELL AND THERE SHOULD BE ENOUGH LLVL
INSTABILITY OUT AHEAD OF THESE CELLS FOR SOME OF THEIR EFFECTS TO AT
LEAST MAKE IT INTO THE SW NC AND NE GA MTNS BY 02-03Z. LATEST MESO
MODEL RUNS SEEM TO BE HANDLING THE UPSTREAM STORMS REASONABLY
WELL...BUT WITH POOR RUN-TO-RUN CONSISTENCY WRT THE EVOLUTION. AN
EARLIER RUN SUGGESTED AN ORGANIZED BAND OF TSTMS DEVELOPING AND
MOVING IN OVERNIGHT...BUT LATEST COUPLE RUNS SHOW THE ACTIVITY
REMAINING UNORGANIZED AND WITH ONLY LIGHT PRECIP MAKING IT INTO THE
CAROLINAS. GIVEN WEAK LLJ AND INCREASING AMT OF LLVL CIN OUT AHEAD
OF THE CELLS...I THINK THAT IS MORE LIKELY. HOWEVER ENUF MOISTURE IS
PRESENT TO EXPECT SOME LIGHT PRECIP TO DEVELOP HERE AS THE WAVE
MOVES IN... SO KEPT CHC POPS FOR MOST AREAS OVERNIGHT FOCUSING MORE
ON THE WEST.
AS OF 220 PM EDT...WATER VAPOR IMAGERY SHOWS A SHORTWAVE BACK ACROSS
AR/MO WITH MORE OF A CHANNELED SPEED MAX ACROSS MIDDLE TN. THE NAM
AND GFS BOTH BRING THIS ENERGY ACROSS THE MOUNTAINS A LITTLE AFTER
00 UTC. MORNING SOUNDINGS STILL HAD A RESPECTABLE INVERSION BETWEEN
700-800 MB...AND IT/S NO SURPRISE THAT CONVECTION HASN/T INITIATED
YET. BUT WE SHOULD SEE SHOWERS AND STORMS BEGIN TO POP OVER THE
MOUNTAINS OVER THE NEXT COUPLE HOURS AS HEIGHTS FALL. IT WILL
PROBABLY TAKE UNTIL SOMETIME BETWEEN 8 PM AND MIDNIGHT BEFORE SCT
CONVECTION REALLY BEGINS TO MAKE AN EASTWARD PUSH. THE CONVECTION
ALLOWING MODELS AREN/T IN GREAT AGREEMENT IN HOW CONVECTION EVOLVES
OVERNIGHT...OFTEN A SIGN THAT WE WON/T SEE A GREAT DEAL OF COVERAGE.
HOWEVER...THE MOS IS GENERALLY IN THE LIKELY RANGE OVER THE MTNS AND
FOOTHILLS...AND I/VE FOLLOWED THAT TREND. POPS OVER THE ERN ZONES
WILL HOLD BETWEEN 30 AND 40 PERCENT OVERNIGHT...THOUGH I DOUBT
ANYTHING WILL DEVELOP THERE UNTIL AFTER SUNSET.
MONDAY IS ALSO NOT A HIGH CONFIDENCE FORECAST. WE WILL CERTAINLY SEE
SCT SHRA/TSTMS...BUT THE GFS HAS THE REGION UNDER WEAK NVA AS THE
WAVE THAT CROSSES THE FA TONIGHT MOVES OFF THE COAST. WE WILL BE
UNDER CYCLONIC CURVATURE AND BY LATE DAY SOME WEAK PVA DOES DEVELOP
AGAIN. BUT EXACTLY HOW AND WHERE CONVECTION EVOLVES ISN/T ALL THAT
CLEAR ATTM. REGARDLESS...WITH WEAK LAPSE RATES...A MOIST ATMOSPHERE
AND ONLY ABOUT 10 KTS OF SPEED SHEAR...SEVERE CHANCES WILL BE LOW
BOTH TONIGHT AND MONDAY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
AT 230 PM EDT SUNDAY...A SLOWLY PROGRESSIVE MEAN UPPER TROUGH AXIS
WILL BE OVER THE EASTERN HALF OF THE NATION FROM MONDAY NIGHT
THROUGH WEDNESDAY. A SHORTWAVE WILL CROSS THE SOUTHERN APPALACHIANS
ON TUESDAY...FOLLOWED BY ANOTHER ON WEDNESDAY.
A NEARLY STATIONARY BAND OF MOISTURE EXTENDING FROM THE COAST TO THE
MOUNTAINS WILL BE OVER OUR AREA ON MONDAY NIGHT THROUGH TUESDAY NIGHT
A SURFACE WAVE ORGANIZES IN THE MID MS RIVER VALLEY MONDAY NIGHT...
THEN MOVES INTO THE SOUTHERN APPALACHIANS ON TUESDAY...AND OFF THE
COAST WEDNESDAY.
MODEL TIME HEIGHTS SHOW DEEP MOISTURE OVER OUR AREA AHEAD OF THE
WAVE...BUT WITH LITTLE TO NO ISENTROPIC UPGLIDE. A LIGHT LOW LEVEL
FLOW VEERS FROM SW TO W...SHIFTING WEAK UPSLOPE FLOW FROM THE SOUTH
FACING BLUE RIDGE ESCARPMENT...TO THE TN BORER. MODEST AMOUNTS OF
CAPE AND SHEAR WILL BE PRESENT. LOW LEVEL MOISTURE MAY LINGER
THROUGH WEDNESDAY...AS A BACK DOOR FRONT MOVES IN FROM THE NORTH ON
THE HEELS OF THE DEPARTING SURFACE WAVE.
TEMPERATURES WILL EXHIBIT A LOWER THAN NORMAL DIURNAL RANGE DUE TO
CLOUD COVER.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 215 PM EDT SUNDAY...THE MEDIUM RANGE FORECAST PERIOD WILL HAVE
TYPICAL PM CONVECTION FOR THIS TIME OF YEAR BUT TEMPERATURES A BIT
ON THE COOL SIDE. THE COLD FRONT WILL BE TO OUR SOUTH AS SURFACE
HIGH PRESSURE TRANSITS FROM WESTERN PA WEDNESDAY NIGHT TO OFF THE
JERSEY COAST THURSDAY NIGHT. DURING THIS TIME A LIGHT NORTHEAST FLOW
WILL USHER IN COOLER THAN NORMAL TEMPERATURES WITH HIGHS ON THURSDAY
ABOUT 3 CATEGORIES BELOW NORMAL. MINOR SHORTWAVES WILL BE ROUNDING
THE TOP OF THE UPPER RIDGE CENTERED NEAR TEXAS COMBINED WITH
AFTERNOON HEATING BRINGS CONVECTION. LOOKING VERTICALLY...THE WIND
WILL GENERALLY BE 10 KNOTS OR LESS IN THE SECOND HALF OF THE WEEK
UNTIL YOU GET TO AROUND 500MB. THE ATMOSPHERE WILL BE RATHER STABLE
THURSDAY AND FRIDAY WITH GREATEST INSTABILITY OVER UPPER SAVANNAH
VALLEY WILL RANGE FROM 800 TO 1100 ON THURSDAY. AFTERNOON CAPES A
LITTLE HIGHER SATURDAY AND SUNDAY. THE LOW AMPLITUDE UPPER TROUGH
WHICH HAD AXIS ALONG THE EAST COAST BACK IN MID WEEK WILL BE
TRANSITIONING OFF THE EAST COAST FOR NEXT WEEKEND WITH THE UPPER
RIDGE ONLY PROGRESSING EAST FROM TEXAS TO PERHAPS ARKANSAS BY THE
END OF THIS CURRENT FORECAST PERIOD SUNDAY NIGHT. BY THAT TIME
TEMPERATURES WILL BE GETTING CLOSE TO NORMAL.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH
THE ONLY EXCEPTIONS BEING LOWERING VISB ADJACENT TO ANY THUNDERSTORM
DEVELOPMENT ON MONDAY AFTERNOON. IN THE NEAR TERM...DECIDED TO PULL
THE PREVIOUS SHRA TEMPO AS LATEST RADAR TRENDS SHOW A GRADUAL DECAY
IN ACTIVITY WELL TO THE WEST. EXPECTING CIGS TO LOWER TO AROUND
10KFT AS UPPER SHORTWAVE TROF PASSES THROUGH TOMORROW MORNING.
LIKEWISE...A GRADUAL INCREASE IN COVERAGE OF SHOWER ACTIVITY IS
EXPECTED THUS PROMPTING MENTION OF -SHRA AROUND 15Z. AS SOME
HEATING OCCURS DURING THE EARLY AFTERNOON HOURS...THERE WILL BE A
CHANCE FOR SOME RATHER DISORGANIZED CONVECTION LEADING TO PROB30 FOR
TSRA THROUGH THE AFTERNOON. SOME LOWER BKN CIGS ARE POSSIBLE LATE
IN THE PERIOD DUE TO OVERSPREADING CONVECTIVE DEBRIS. WINDS WILL
GENERALLY BE LIGHT AND SOUTHERLY.
ELSEWHERE...LOOK FOR VFR CONDITIONS TO PERSIST THROUGH THE TAF
PERIOD ASIDE FOR VISB RESTRICTIONS DUE TO THUNDERSTORM DEVELOPMENT
MONDAY AFTERNOON. AS WITH KCLT ABOVE...EXPECTING COVERAGE OF
SHOWERS TO INCREASE THROUGH THE MORNING HOURS IN RESPONSE TO UPPER
TROF. MODELS INDICATE THE BEST INSTABILITY TO BE AROUND THE 15-18Z
TIMEFRAME ACROSS THE FOOTHILLS OF NORTH CAROLINA...AND THE
UPSTATE/PIEDMONT REGIONS OF SOUTH CAROLINA. THUS...WENT WITH TEMPO
GROUPS FOR TSRA AT ALL CORRESPONDING SITES FOR THIS PERIOD. BEYOND
THAT... EXPECTING LESS THUNDERSTORM PERSISTENCE THUS REVERTED TO
-SHRA WITH VCTS MENTION IN THE TAFS. SHOWER ACTIVITY WILL TAPER OFF
FROM NORTH TO SOUTH MONDAY EVENING THEREFORE KEPT VCSH AT ALL SOUTH
CAROLINA SITES.
OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% MED 73%
KGSP HIGH 100% HIGH 100% HIGH 100% MED 73%
KAVL HIGH 97% HIGH 97% HIGH 100% HIGH 80%
KHKY HIGH 100% HIGH 100% HIGH 100% MED 73%
KGMU HIGH 100% HIGH 100% HIGH 100% MED 73%
KAND HIGH 100% HIGH 99% HIGH 100% MED 73%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...MCAVOY/WIMBERLEY
SHORT TERM...JAT
LONG TERM...DEO
AVIATION...CDG
000
FXUS62 KCAE 170540
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
140 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST HAS SHIFTED FARTHER EASTWARD
AHEAD OF A WEAK FRONTAL ZONE MOVING SOUTHWARD AND INTO THE FORECAST
AREA. THE FRONT AND ASSOCIATED MOISTURE WILL DOMINATE THE FORECAST
AREA/S WEATHER THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
THE MID-LEVEL SHORTWAVE TROUGH APPROACHING THE FORECAST AREA THIS
MORNING HAS REMOVED THE CAPPING THAT HAS BEEN DOMINATE DURING THE
PAST FEW DAYS. MOISTURE HAS INCREASED AHEAD OF THE DIFFUSE FRONT
DROPPING SOUTHWARD AND TOWARD THE FORECAST AREA. THE NAM AND GFS
SHOW MOISTURE CONTINUING TO INCREASE WITH PRECIPITABLE WATER NEAR
2 INCHES. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TODAY.
CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM INDICATES SURFACE-
BASED LI/S -4 TO -5 TODAY. THE THREAT OF SEVERE THUNDERSTORMS
APPEARS LOW BECAUSE OF THE LIMITED INSTABILITY. AN AVERAGE OF THE
NAM AND GFS PLUS THE SREF MEAN SUPPORT GENERAL RAIN AMOUNTS NEAR
ONE-HALF OF AN INCH. HEAVY RAIN MAY OCCUR BECAUSE OF THE HIGH
PRECIPITABLE WATER AND SLOW MOVEMENT AND POSSIBLE TRAINING. LEANED
TOWARD THE COOLER TEMPERATURE GUIDANCE TODAY BECAUSE OF CLOUDINESS.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
HIGH MOISTURE ASSOCIATED WITH THE DIFFUSE EAST-WEST ORIENTED FRONT
WILL CONTINUE. THE MODELS KEEP BROAD UPPER-LEVEL TROUGHING WITH A
SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW OVER THE
FORECAST AREA. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS. LEANED
TOWARD THE HIGHER GUIDANCE POPS. THE COOLER HIGH TEMPERATURE
GUIDANCE APPEARS BETTER BECAUSE OF EXPECTED CLOUDINESS. THE LOW
TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY THE FRONT REMAINING NEAR THE FORECAST
AREA THROUGH THE MEDIUM-RANGE PERIOD. THERE HAS BEEN INCONSISTENCY
IN THE PLACEMENT OF DEEPER MOISTURE. THE GFS ENSEMBLE MEANS AND
OPERATIONAL GFS MOS SUPPORT CHANCE POPS THROUGH THE PERIOD.
EXPECT HIGH TEMPERATURES NEAR OR A LITTLE BELOW CLIMATOLOGY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
A BAND OF SHOWERS AND THUNDERSTORMS CURRENTLY OVER NRN GA MOVING
EAST. AN UPPER DISTURBANCE MAY ALLOW SOME OF THIS ACTIVITY TO SHIFT
EASTWARD INTO UPSTATE SC DURING THE EARLY MORNING HOURS. MODELS SEEM
TO BE HINTING THAT THIS CONVECTIVE ACTIVITY SHOULD REMAIN NORTH AND
WEST OF THE TAF SITES THROUGH 12Z. LATEST CAE VAD WIND PROFILE
INDICATING SW WINDS AROUND 30 KNOTS AT 2000 FEET. NAM BUFKIT
INDICATING DEEPEST MOISTURE AROUND 3000-4000 FEET OVERNIGHT SO HAVE
INCLUDED TEMPO GROUP BEFORE SUNRISE FOR SOME MVFR CIGS. THESE
FACTORS ALONG WITH SOME MID/HIGH LEVEL CONVECTIVE DEBRIS CLOUDINESS
WOULD WORK AGAINST FOG FORMATION. AFTER ANY MORNING
RESTRICTIONS...VFR EXPECTED MONDAY OUTSIDE OF ANY CONVECTION. A
DEEPENING UPPER TROUGH AND INCREASING ATMOSPHERIC MOISTURE IS
EXPECTED TO LEAD TO SCATTERED THUNDERSTORMS MONDAY
AFTERNOON...MAINLY AFTER 18Z. HAVE MENTION SHRA AFTER 21Z AT ALL TAF
SITES BUT TSRA MAY BE POSSIBLE AS WELL. WILL CONTINUE MENTION OF
SHRA IN THE TAFS TOWARDS THE END OF THE TAF PERIOD AS A SLOW-MOVING
COLD FRONT APPROACHES FROM THE OH RIVER VALLEY.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 170520
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
120 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL BUILD TO THE NORTH INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
NO MAJOR CHANGES WERE MADE FOR THE EARLY MORNING UPDATE. SHOWERS
MOVING ACROSS NORTHERN GEORGIA ARE SLOWLY DIMINISHING WITH TIME
AND ITS UNCLEAR WHETHER THEY WILL MAKE IT INTO THE WESTERN ZONES
PRIOR TO SUNRISE. MAINTAINED SLIGHT CHANCE POPS IN THESE AREAS
JUST IN CASE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
MONDAY...AN IMMENSE MID AND UPPER LEVEL TROUGH WILL BE FOUND OVER SE
CANADA...WHILE A FLAT AND STRETCHED OUT RIDGE IS LOCATED FROM THE SW
ATLANTIC ACROSS THE GULF AND NORTHERN OLD MEXICO INTO THE SE
PACIFIC. THE LOCAL REGIME WILL LIE NEAR THE SOUTHERN EXTENSION OF A
SLIGHTLY CYCLONIC FLOW ALOFT...WITH WEAK ENTRENCHED SHORT WAVES
FOUND WITHIN THE SOUTHERN STREAM OF THE JET. ONE OF THESE FEATURES
WILL TRIGGER THE DEVELOPMENT OF A VERY WEAK WARM FRONT OR TROUGH
ACROSS SOUTHERN GA IN THE AFTERNOON...AS THE LAST OF THE BERMUDA
SURFACE HIGH STRIVES TO HANG ON. THE MOST NOTICEABLE CHANGES IN THE
AIR MASS WILL BE THE RETURN OF HIGHER DEW POINTS...MUCH GREATER
MOISTURE AS PWATS TOP OUT NEAR 1.8 TO 1.9 INCHES AND WARMER TEMPS.
ALL THIS IS COURTESY OF THE RETURN FLOW AROUND THE ATLANTIC RIDGE.
INSTABILITY AND ESPECIALLY CAPE WILL BE AT HIGHER VALUES...THE
PERSISTENT SUBSIDENCE CAP WILL HAVE ERODED WHILE CINH WANES
THROUGHOUT THE DAY...AND THERE IS A LITTLE COOLER CONDITIONS IN THE
MID LEVELS. THE COMBINED INFLUENCES WILL ALLOW FOR THE RESUMPTION OF
OUR TYPICAL WARM SEASON CONVECTION...TRIGGERED BY THE SEA
BREEZE...THE SOUTHERN GA TOUGH OR WARM FRONT AND UPSTREAM BOUNDARIES
THAT COULD DRIFT IN WITH THE WESTERLY FLOW. DUE TO A SLOW STORM
MOTION OF NO MORE THAN ABOUT 10 KT AND THE ELEVATED PWATS...LOCALLY
HEAVY RAINS CAN OCCUR IN SOME OF THE MORE PERSISTENT STORMS.
CONVECTION WILL HOLD OFF UNTIL LATE MORNING OR EARLY AFTERNOON WHEN
WE REACH OUR TRIGGER TEMPS...WITH HIGHEST AFTERNOON COVERAGE MAINLY
IN THE SCATTERED RANGE...FROM 30 POPS NEAR THE COAST TO 50 POPS FAR
INLAND. DESPITE PARTLY TO MOSTLY CLOUDY SKY CONDITIONS...WARM
ADVECTION AND A STRETCHING OF THE LOW LEVEL THICKNESS WILL GENERATE
MAX TEMPS WITHIN A DEGREE OR TWO EITHER SIDE OF 90 INLAND FROM THE
INTRACOASTAL WATERS.
MONDAY NIGHT...ALTHOUGH THERE IS A RETURN TO THE CINH AS PER
SOUNDINGS...GIVEN THAT THE SURF ACE TROUGH OR WARM FRONT WILL LIFT
THROUGH THE FORECAST AREA AND THERE IS SOME SHORT WAVE ENERGY
ALOFT...WE FEEL THAT SLIGHT CHANCE AND CHANCE POPS ARE JUSTIFIED
DESPITE THE NOCTURNAL ENVIRONMENT. OUR GRIDS WILL SHOW THE GREATEST
POPS ALONG THE NW RANGE OF THE CWFA DURING THE EVENING...THEN
TRANSITIONING TO OVER THE CHARLESTON TRI-COUNTY ZONES LATE AT NIGHT
IN PROXIMITY TO THE SURFACE FEATURE. MINIMUM TEMPS WILL BE NEAR OR
SLIGHTLY ABOVE NORMAL.
TUESDAY THROUGH WEDNESDAY...THE LARGE SCALE PATTERN ACROSS THE NORTH
AMERICAN CONTINENT WILL BE HIGHLY AMPLIFIED AND SOMEWHAT PROGRESSIVE
THROUGH THE PERIOD. LOCALLY WE WILL LIE NEAR THE SOUTHERN REACHES OF
CYCLONIC FLOW OVER THE EASTERN UNITED STATES...WITH PERIODIC MID
LEVEL PERTURBATIONS TO PASS ON THROUGH. SIMULTANEOUSLY AT THE
SURFACE WE WILL FIND A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE
VALLEY ON TUESDAY THAT STRUGGLES TO PUSH SE THROUGH WEDNESDAY. THE
FRONT BECOMES ORIENTED MORE PARALLEL TO THE FLOW ALOFT...WHILE AT
THE SAME TIME WAVES OF LOW PRESSURE PREVENT THE FRONT FROM SHIFTING
SOUTH AND SE AT MORE THAN A CRAWL. PRESENTLY IT LOOKS LIKE WE WILL
REMAIN IN THE WARM SECTOR SOUTH OF THE FRONT THROUGH THE MIDDLE OF
THE WEEK...AWAITING THE FORMATION OF ONE LAST WAVE THAT CLOSES INTO
A LOW OFF THE NC COAST LATE WEDNESDAY OR WEDNESDAY NIGHT. THERE IS
AMPLE INSTABILITY AND MOISTURE TO PRODUCE AT LEAST SCATTERED
CONVECTION. THERMODYNAMICS ARE NOT OVERLY IMPRESSIVE IN REGARDS TO
SEVERE WEATHER...BUT AT THIS TIME OF YEAR THERE IS ALWAYS AT
LEAST AN ISOLATED RISK SHOULD ANY BOUNDARY INTERACTIONS RESULT IN
STRONGER UPDRAFTS. COMPRESSIONAL HEATING IN ADVANCE OF THE COLD
FRONT FRONT...AIDED BY A DEEP WESTERLY FLOW OFF THE APPALACHIANS
WILL ALLOW FOR MANY LOCATIONS TO PEAK AT OR ABOVE 90 EACH AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WITH THE CENTER OF UPPER LEVEL RIDGING REMAINING WELL WEST OF THE
REGION THROUGH THE PERIOD...THE PATTERN ALOFT WILL BE SOMEWHAT ILL
DEFINED AND PROGRESSIVE INTO AT LEAST LATE WEEK. THUS EXPECT
UNSETTLED CONDITIONS TO PERSIST INTO THE EXTENDED FORECAST
PERIOD...WITH FORECAST DETAILS QUITE UNCERTAIN DUE TO MODEL
INCONSISTENCIES. THE LINGERING FRONT OVER OR NEAR THE FORECAST
AREA...WHEN COMBINED WITH WEAK SHORTWAVE ENERGY EMBEDDED WITHIN
UPPER TROUGHING...WILL MAINTAIN DEEP MOISTURE AND CONVERGENCE TO
SUPPORT THUNDERSTORM CHANCES EACH DAY. MEDIUM RANGE MODELS DO
SUGGEST THAT THE SURFACE PATTERN WILL EVENTUALLY SETTLE TOWARD HIGH
PRESSURE TO THE NORTH AND A COASTAL TROUGH DEVELOPING ALONG THE
PERSISTENT FRONT TO THE SOUTH AND EAST. HIGH TEMPERATURES WILL VARY
LITTLE EACH AFTERNOON...REACHING THE UPPER 80S TO AROUND 90 DEGREES
AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
GENERALLY VFR. RISK FOR SHOWERS/TSTMS WILL INCREASE LATER THIS
MORNING AND INTO THE AFTERNOON. MODELS GENERALLY FAVOR THE
CORRIDOR OF GREATEST COVERAGE REMAINING TO THE WEST OF THE KCHS-
KSAV CORRIDOR...ALTHOUGH SOME OF THE HIGHER RESOLUTION DATA
SUGGEST KCHS MAY HAVE A BETTER SHOW LATER THIS AFTERNOON FOR
IMPACTS. WILL TEMPO 19-21Z FOR 4SM TSRA BR SCT015 BKN035CB TO
COVER FOR NOW. WILL LEAVE TSRA OUT OF THE KSAV TAF UNTIL CONFIDENCE
INCREASES. AMENDMENTS WILL MOST CERTAINLY BE NEEDED THROUGHOUT
THE DAY AS MESOSCALE AND SHORT TERM RADAR TRENDS BECOME MORE
APPARENT.
EXTENDED AVIATION...PERIODIC FLIGHT RESTRICTIONS MONDAY NIGHT
THROUGH THURSDAY IN ASSOCIATION WITH SCATTERED TO NUMEROUS
SHRA/TSRA.
&&
.MARINE...
OVERNIGHT...S/SE ACROSS GA WATERS AND S/SW WINDS ACROSS SC WATERS
WILL AVERAGE 10-14 KT...ACCOMPANIED BY 2-3 FT SEAS.
MONDAY AND MONDAY NIGHT...THE LOCAL DOMAIN WILL BE PLACED WITHIN THE
WEST AND NW PORTION OF THE SUB-TROPICAL ATLANTIC RIDGE MONDAY THAT
GRADUALLY GIVES WAY TO A WEAK WARM FRONT OR SURFACE TROUGH THAT
PROGRESSES THROUGH MONDAY NIGHT. WHILE THERE WILL BE SOME INCREASE
IN WINDS WITH THE SEA BREEZE CIRCULATION MONDAY AFTERNOON AND WITH
NOCTURNAL LOW LEVEL JETTING MONDAY NIGHT...SOUTH AND SW WINDS WILL
GENERALLY HOLD UNDER 15-17 KT. SEAS AROUND 2-3 FEET MONDAY WILL RISE
ABOUT ANOTHER FOOT MONDAY NIGHT. ISOLATED TO SCATTERED CONVECTION
WILL FINALLY MAKE A RETURN TO THE COASTAL WATERS DURING THIS TIME.
TUESDAY THROUGH WEDNESDAY...THE QUASI-WARM FRONT OR SURFACE TROUGH
WILL LIFT NORTH OF THE MARINE COMMUNITY EARLY IN THE PERIOD...WHILE
WE FIND THE ATLANTIC RIDGE SUBDUED TO THE SOUTH. MEANWHILE...AN
UPSTREAM COLD FRONT WILL RELUCTANTLY MAKE A SE PUSH TOWARD THE
WATERS TUESDAY NIGHT AND WEDNESDAY. STILL TOO MUCH UNCERTAINTY AS TO
HOW FAR THE FRONT WILL BE ABLE TO PENETRATE...AS THE OCEANIC RIDGE
TO THE SOUTH AND SE ATTEMPTS TO HOLD FIRM. WE DO FEEL CONFIDENT THAT
WINDS AND SEAS WILL ASCEND TUESDAY AND TUESDAY NIGHT...WITH A
TIGHTENING OF THE PRESSURE GRADIENT BETWEEN THE UPSTREAM COLD FRONT
AND THE ATLANTIC HIGH. EVEN SO...ODDS AT THIS STAGE ARE AGAINST ANY
SMALL CRAFT ADVISORY CONDITIONS. WIND AND SEA CONDITIONS WILL THEN
BE DETERMINED BY WHERE THE FRONT ALIGNS ITSELF ON WEDNESDAY...BUT NO
MATTER WHERE IT IS LOCATED...ADVISORY HEADLINES ARE NOT ANTICIPATED.
MARINERS ARE ADVISED THAT AT LEAST SCATTERED CONVECTION WILL
OCCUR...AND WE/LL MAINTAIN A WEATHER WATCH FOR THE POSSIBLE
ORGANIZATION OF STRONGER STORMS MOVING OFF THE COAST IN ADVANCE OF
THE COLD FRONT.
THURSDAY THROUGH FRIDAY...THE FRONT LOOKS TO BECOME MORE DIFFUSE
NEAR OR JUST SE OF THE LOCAL WATERS...AS HIGH PRESSURE BUILDS OVER
NEW ENGLAND AND THE MID ATLANTIC REGION. WINDS AND SEAS WILL BE WELL
BELOW ANY CRITERIA FOR SMALL CRAFT ADVISORIES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
000
FXUS62 KCAE 170509
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
109 AM EDT MON JUN 17 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL WEAKEN OVERNIGHT. A WEAK SYSTEM
WILL APPROACH FROM THE WEST MONDAY BRINGING A SLOW MOVING COLD
FRONT AND INCREASING THE MOISTURE ACROSS THE REGION MONDAY
THROUGH TUESDAY. AN INCREASE IN THE CHANCES OF SHOWERS AND
THUNDERSTORMS IS ALSO EXPECTED MONDAY THROUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CURRENT REGIONAL RADAR MOSAIC SHOWING A LINE OF SHOWERS AND
THUNDERSTORMS IN NORTHWESTERN GA STRETCHING INTO THE WESTERN
CAROLINAS ASSOCIATED WITH A SHORTWAVE. CLOUD COVER WILL INCREASE
FROM WEST TO EAST OVERNIGHT AS THE SHORTWAVE APPROACHES FROM THE
WEST. INCREASING CLOUDS WILL PREVENT TEMPS FROM DROPPING AS LOW AS
THE PAST COUPLE OF NIGHTS...WITH NEAR NORMAL LOWS IN THE UPPER 60S
EXPECTED. GUIDANCE IS IN GOOD AGREEMENT WITH TEMPS. MODELS SHOW
THE SHORTWAVE CROSSING THE AREA EARLY MONDAY... WHICH COULD HELP
INITIATE SOME SHOWER ACTIVITY. INCREASED POPS TO SLIGHT CHANCE...BUT
CONFIDENCE REMAINS LOW REGARDING STRENGTH OF THE SHORTWAVE AND HOW
WELL PRECIPITATION WILL HOLD TOGETHER AS IT MOVES TOWARD THE AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
A MID-UPPER LEVEL TROUGH WILL MOVE INTO THE REGION MONDAY
THROUGH TUESDAY WITH A COUPLE WEAK SHORT WAVES TRAVERSING
THE AREA MONDAY AND AGAIN ON TUESDAY. IN ADDITION...INCREASING
LOW LEVEL SOUTHWEST WIND FLOW WILL ADVECT MOISTURE INTO THE
FORECAST AREA. ALONG WITH THE INCREASE IN MOISTURE...THERE
WILL BE OVERNIGHT LOW CLOUDS IN THE FORM OF STRATUS BOTH
MONDAY MORNING AND TUESDAY MORNING. DAYTIME HEATING WILL
HELP BREAK UP THE LOW CLOUD DECK BUT THERE SHOULD BE PLENTY
OF MOISTURE FOR SHOWERS AND THUNDERSTORMS TO DEVELOP BOTH
MONDAY AND TUESDAY. PLAN ON CONTINUING THE 40-50 PERCENT
CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY THROUGH TUESDAY.
CLOUDS ARE EXPECTED TO HOLD HIGHS BELOW 90 IN THE UPPER 80S
MONDAY AND MORE CLOUDS ON TUESDAY SHOULD HOLD HIGHS INTO THE
MIDDLE 80S. OVERNIGHT LOWS MONDAY NIGHT SHOULD BE RIGHT AROUND
70 AND IN THE LOWER 70S TUESDAY NIGHT. IN ADDITION...RAIN
CHANCES CONTINUE NEAR 40 PERCENT TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF APPEAR TO BE IN PRETTY GOOD AGREEMENT
WEDNESDAY THROUGH SUNDAY. THE MID-UPPER LEVEL TROUGH REMAINS
NEAR THE EAST COAST AT LEAST THROUGH FRIDAY...THEN AN UPPER
RIDGE TO THE WEST TRIES TO NUDGE IN FOR THE WEEKEND. HOWEVER
THERE APPEARS TO BE A CHANCE OF SHOWERS AND THUNDERSTORMS
EACH DAY. THE HIGHEST CHANCES ARE EARLY IN THE PERIOD
WEDNESDAY THROUGH FRIDAY WITH A 30-40 PERCENT CHANCE. AS
THE UPPER RIDGE TRIES TO BUILD EAST...RAIN CHANCES DROP
A BIT TO 20-30 PERCENT FOR SATURDAY AND SUNDAY AND THE
CONVECTIVE ACTIVITY SHOULD BECOME MORE DIURNAL OR SUMMER
LIKE IN NATURE. HIGHS ARE A BIT BELOW NORMAL MAINLY IN
THE MIDDLE 80S WEDNESDAY AND THURSDAY BUT INCREASE TO
THE UPPER 80S BY SATURDAY AND SUNDAY BUT THERE MAY BE
A FEW 90S AROUND SUNDAY DEPENDING ON THE AMOUNT OF SUNSHINE.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
A BAND OF SHOWERS AND THUNDERSTORMS CURRENTLY OVER NRN GA MOVING
EAST. AN UPPER DISTURBANCE MAY ALLOW SOME OF THIS ACTIVITY TO SHIFT
EASTWARD INTO UPSTATE SC DURING THE EARLY MORNING HOURS. MODELS SEEM
TO BE HINTING THAT THIS CONVECTIVE ACTIVITY SHOULD REMAIN NORTH AND
WEST OF THE TAF SITES THROUGH 12Z. LATEST CAE VAD WIND PROFILE
INDICATING SW WINDS AROUND 30 KNOTS AT 2000 FEET. NAM BUFKIT
INDICATING DEEPEST MOISTURE AROUND 3000-4000 FEET OVERNIGHT SO HAVE
INCLUDED TEMPO GROUP BEFORE SUNRISE FOR SOME MVFR CIGS. THESE
FACTORS ALONG WITH SOME MID/HIGH LEVEL CONVECTIVE DEBRIS CLOUDINESS
WOULD WORK AGAINST FOG FORMATION. AFTER ANY MORNING
RESTRICTIONS...VFR EXPECTED MONDAY OUTSIDE OF ANY CONVECTION. A
DEEPENING UPPER TROUGH AND INCREASING ATMOSPHERIC MOISTURE IS
EXPECTED TO LEAD TO SCATTERED THUNDERSTORMS MONDAY
AFTERNOON...MAINLY AFTER 18Z. HAVE MENTION SHRA AFTER 21Z AT ALL TAF
SITES BUT TSRA MAY BE POSSIBLE AS WELL. WILL CONTINUE MENTION OF
SHRA IN THE TAFS TOWARDS THE END OF THE TAF PERIOD AS A SLOW-MOVING
COLD FRONT APPROACHES FROM THE OH RIVER VALLEY.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 170242
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1042 PM EDT SUN JUN 16 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL WEAKEN OVERNIGHT. A WEAK SYSTEM
WILL APPROACH FROM THE WEST MONDAY BRINGING A SLOW MOVING COLD
FRONT AND INCREASING THE MOISTURE ACROSS THE REGION MONDAY
THROUGH TUESDAY. AN INCREASE IN THE CHANCES OF SHOWERS AND
THUNDERSTORMS IS ALSO EXPECTED MONDAY THROUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
CURRENT REGIONAL RADAR MOSAIC SHOWING A LINE OF SHOWERS AND
THUNDERSTORMS IN NORTHWESTERN GA STRETCHING INTO THE WESTERN
CAROLINAS ASSOCIATED WITH A SHORTWAVE. CLOUD COVER WILL INCREASE
FROM WEST TO EAST OVERNIGHT AS THE SHORTWAVE APPROACHES FROM THE
WEST. INCREASING CLOUDS WILL PREVENT TEMPS FROM DROPPING AS LOW AS
THE PAST COUPLE OF NIGHTS...WITH NEAR NORMAL LOWS IN THE UPPER 60S
EXPECTED. GUIDANCE IS IN GOOD AGREEMENT WITH TEMPS. MODELS SHOW
THE SHORTWAVE CROSSING THE AREA EARLY MONDAY... WHICH COULD HELP
INITIATE SOME SHOWER ACTIVITY. INCREASED POPS TO SLIGHT CHANCE...BUT
CONFIDENCE REMAINS LOW REGARDING STRENGTH OF THE SHORTWAVE AND HOW
WELL PRECIPITATION WILL HOLD TOGETHER AS IT MOVES TOWARD THE AREA.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
A MID-UPPER LEVEL TROUGH WILL MOVE INTO THE REGION MONDAY
THROUGH TUESDAY WITH A COUPLE WEAK SHORT WAVES TRAVERSING
THE AREA MONDAY AND AGAIN ON TUESDAY. IN ADDITION...INCREASING
LOW LEVEL SOUTHWEST WIND FLOW WILL ADVECT MOISTURE INTO THE
FORECAST AREA. ALONG WITH THE INCREASE IN MOISTURE...THERE
WILL BE OVERNIGHT LOW CLOUDS IN THE FORM OF STRATUS BOTH
MONDAY MORNING AND TUESDAY MORNING. DAYTIME HEATING WILL
HELP BREAK UP THE LOW CLOUD DECK BUT THERE SHOULD BE PLENTY
OF MOISTURE FOR SHOWERS AND THUNDERSTORMS TO DEVELOP BOTH
MONDAY AND TUESDAY. PLAN ON CONTINUING THE 40-50 PERCENT
CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY THROUGH TUESDAY.
CLOUDS ARE EXPECTED TO HOLD HIGHS BELOW 90 IN THE UPPER 80S
MONDAY AND MORE CLOUDS ON TUESDAY SHOULD HOLD HIGHS INTO THE
MIDDLE 80S. OVERNIGHT LOWS MONDAY NIGHT SHOULD BE RIGHT AROUND
70 AND IN THE LOWER 70S TUESDAY NIGHT. IN ADDITION...RAIN
CHANCES CONTINUE NEAR 40 PERCENT TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF APPEAR TO BE IN PRETTY GOOD AGREEMENT
WEDNESDAY THROUGH SUNDAY. THE MID-UPPER LEVEL TROUGH REMAINS
NEAR THE EAST COAST AT LEAST THROUGH FRIDAY...THEN AN UPPER
RIDGE TO THE WEST TRIES TO NUDGE IN FOR THE WEEKEND. HOWEVER
THERE APPEARS TO BE A CHANCE OF SHOWERS AND THUNDERSTORMS
EACH DAY. THE HIGHEST CHANCES ARE EARLY IN THE PERIOD
WEDNESDAY THROUGH FRIDAY WITH A 30-40 PERCENT CHANCE. AS
THE UPPER RIDGE TRIES TO BUILD EAST...RAIN CHANCES DROP
A BIT TO 20-30 PERCENT FOR SATURDAY AND SUNDAY AND THE
CONVECTIVE ACTIVITY SHOULD BECOME MORE DIURNAL OR SUMMER
LIKE IN NATURE. HIGHS ARE A BIT BELOW NORMAL MAINLY IN
THE MIDDLE 80S WEDNESDAY AND THURSDAY BUT INCREASE TO
THE UPPER 80S BY SATURDAY AND SUNDAY BUT THERE MAY BE
A FEW 90S AROUND SUNDAY DEPENDING ON THE AMOUNT OF SUNSHINE.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
A BAND OF SHOWERS AND THUNDERSTORMS CURRENTLY OVER NW GA/NE
ALA...SHIFTING EAST. AN UPPER DISTURBANCE MAY ALLOW SOME OF THIS
ACTIVITY TO SHIFT EASTWARD INTO NE GA/UPSTATE SC LATE THIS EVENING
AND EARLY TONIGHT. SOME OF THE HIGH RES SHORT TERM MODEL GUIDANCE
DOES NOT APPEAR TO BE HANDLING THIS CONVECTION PARTICULARLY WELL
THIS EVENING...BUT A REVIEW OF MODEL GUIDANCE GENERALLY SUGGESTS
THAT MUCH OF THIS ACTIVITY SHOULD REMAIN NORTH OF OUR TERMINALS.
LATEST SPC MESOANALYSIS CURRENTLY INDICATES MORE STABLE AIR OVER OUR
FA...THAN TO OUR WEST. BUFKIT INDICATES A 25 KNOT BOUNDARY LAYER
FLOW FROM THE SW OVERNIGHT. THIS ALONG WITH SOME MID/HIGH LEVEL
CONVECTIVE DEBRIS CLOUDINESS WOULD WORK AGAINST FOG FORMATION. SOME
OF THE LATEST GUIDANCE SUGGESTING SOME STRATUS POSSIBLE...FAVORING
THE WEST FA/CSRA...WHICH MAKES SENSE GIVEN BETTER MOISTURE AND
PRECIP POTENTIAL TO OUR WEST...BUT LATEST GFS LAMP NOT AS BULLISH ON
STRATUS POTENTIAL. SO...CONFIDENCE LIMITED AT THIS TIME DUE TO MODEL
DISAGREEMENT. WILL NOT MENTION IFR AT THIS TIME DUE TO LIMITED
CONFIDENCE...BUT WILL MAINTAIN TEMPO MENTION OF MVFR CONDITIONS LATE
TONIGHT/EARLY MONDAY. AFTER ANY MORNING RESTRICTIONS...VFR EXPECTED
MONDAY OUTSIDE OF ANY CONVECTION. A DEEPENING UPPER TROUGH AND
INCREASING ATMOSPHERIC MOISTURE IS EXPECTED TO LEAD TO SCATTERED
THUNDERSTORMS MONDAY AFTERNOON...MAINLY AFTER 18Z. CHANCES OF IT
AFFECTING TERMINALS TOO LOW TO INCLUDE MENTION IN THE TAFS AT THIS
TIME.
EXTENDED AVIATION OUTLOOK...CHANCE OF MAINLY AFTERNOON/EVENING
THUNDERSTORMS. CHANCE OF LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 170237
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1037 PM EDT SUN JUN 16 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT FARTHER INTO THE ATLANTIC
EARLY THIS WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY...THEN SLOWLY PROGRESS THROUGH THE AREA WEDNESDAY AND
THURSDAY. HIGH PRESSURE WILL BUILD TO THE NORTH INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE 00Z KCHS RAOB DEPICTED THE RESIDUAL INFLUENCE OF DEEP LAYER
RIDGING/SUBSIDENCE OVER THE REGION...PROVIDING A MOSTLY CLEAR AND
TRANQUIL EVENING/EARLY OVERNIGHT. UPSTREAM...MULTICELL
THUNDERSTORMS WERE ADVANCING ACROSS N GA AND INTO THE SC UPSTATE.
CONVECTION WILL MAKE A RUN AT FORECAST AREA OVERNIGHT AND COULD PUSH
INTO INLAND COUNTIES IN A WEAKENED FORM LATE...THUS INTRODUCED
SLIGHT CHANCE POPS LATE TONIGHT.
TEMPERATURES WILL BOTTOM OUT IN THE MID/UPPER 60S AT MANY
LOCATIONS AWAY FROM THE IMMEDIATE COAST. LATE TONIGHT...TEMPERATURES
COULD BECOME UNSTEADY OR EVEN RISE A FEW DEGREES AS CLOUDS BEGIN
TO OVERSPREAD THE REGION. ON THE BEACHES...TEMPERATURES WILL
REMAIN IN THE MID/UPPER 70S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
MONDAY...AN IMMENSE MID AND UPPER LEVEL TROUGH WILL BE FOUND OVER SE
CANADA...WHILE A FLAT AND STRETCHED OUT RIDGE IS LOCATED FROM THE SW
ATLANTIC ACROSS THE GULF AND NORTHERN OLD MEXICO INTO THE SE
PACIFIC. THE LOCAL REGIME WILL LIE NEAR THE SOUTHERN EXTENSION OF A
SLIGHTLY CYCLONIC FLOW ALOFT...WITH WEAK ENTRENCHED SHORT WAVES
FOUND WITHIN THE SOUTHERN STREAM OF THE JET. ONE OF THESE FEATURES
WILL TRIGGER THE DEVELOPMENT OF A VERY WEAK WARM FRONT OR TROUGH
ACROSS SOUTHERN GA IN THE AFTERNOON...AS THE LAST OF THE BERMUDA
SURFACE HIGH STRIVES TO HANG ON. THE MOST NOTICEABLE CHANGES IN THE
AIR MASS WILL BE THE RETURN OF HIGHER DEW POINTS...MUCH GREATER
MOISTURE AS PWATS TOP OUT NEAR 1.8 TO 1.9 INCHES AND WARMER TEMPS.
ALL THIS IS COURTESY OF THE RETURN FLOW AROUND THE ATLANTIC RIDGE.
INSTABILITY AND ESPECIALLY CAPE WILL BE AT HIGHER VALUES...THE
PERSISTENT SUBSIDENCE CAP WILL HAVE ERODED WHILE CINH WANES
THROUGHOUT THE DAY...AND THERE IS A LITTLE COOLER CONDITIONS IN THE
MID LEVELS. THE COMBINED INFLUENCES WILL ALLOW FOR THE RESUMPTION OF
OUR TYPICAL WARM SEASON CONVECTION...TRIGGERED BY THE SEA
BREEZE...THE SOUTHERN GA TOUGH OR WARM FRONT AND UPSTREAM BOUNDARIES
THAT COULD DRIFT IN WITH THE WESTERLY FLOW. DUE TO A SLOW STORM
MOTION OF NO MORE THAN ABOUT 10 KT AND THE ELEVATED PWATS...LOCALLY
HEAVY RAINS CAN OCCUR IN SOME OF THE MORE PERSISTENT STORMS.
CONVECTION WILL HOLD OFF UNTIL LATE MORNING OR EARLY AFTERNOON WHEN
WE REACH OUR TRIGGER TEMPS...WITH HIGHEST AFTERNOON COVERAGE MAINLY
IN THE SCATTERED RANGE...FROM 30 POPS NEAR THE COAST TO 50 POPS FAR
INLAND. DESPITE PARTLY TO MOSTLY CLOUDY SKY CONDITIONS...WARM
ADVECTION AND A STRETCHING OF THE LOW LEVEL THICKNESS WILL GENERATE
MAX TEMPS WITHIN A DEGREE OR TWO EITHER SIDE OF 90 INLAND FROM THE
INTRA-COASTAL WATERS.
MONDAY NIGHT...ALTHOUGH THERE IS A RETURN TO THE CINH AS PER
SOUNDINGS...GIVEN THAT THE SURF ACE TROUGH OR WARM FRONT WILL LIFT
THROUGH THE FORECAST AREA AND THERE IS SOME SHORT WAVE ENERGY
ALOFT...WE FEEL THAT SLIGHT CHANCE AND CHANCE POPS ARE JUSTIFIED
DESPITE THE NOCTURNAL ENVIRONMENT. OUR GRIDS WILL SHOW THE GREATEST
POPS ALONG THE NW RANGE OF THE CWFA DURING THE EVENING...THEN
TRANSITIONING TO OVER THE CHARLESTON TRI-COUNTY ZONES LATE AT NIGHT
IN PROXIMITY TO THE SURFACE FEATURE. MINIMUM TEMPS WILL BE NEAR OR
SLIGHTLY ABOVE NORMAL.
TUESDAY THROUGH WEDNESDAY...THE LARGE SCALE PATTERN ACROSS THE NORTH
AMERICAN CONTINENT WILL BE HIGHLY AMPLIFIED AND SOMEWHAT PROGRESSIVE
THROUGH THE PERIOD. LOCALLY WE WILL LIE NEAR THE SOUTHERN REACHES OF
CYCLONIC FLOW OVER THE EASTERN UNITED STATES...WITH PERIODIC MID
LEVEL PERTURBATIONS TO PASS ON THROUGH. SIMULTANEOUSLY AT THE
SURFACE WE WILL FIND A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE
VALLEY ON TUESDAY THAT STRUGGLES TO PUSH SE THROUGH WEDNESDAY. THE
FRONT BECOMES ORIENTED MORE PARALLEL TO THE FLOW ALOFT...WHILE AT
THE SAME TIME WAVES OF LOW PRESSURE PREVENT THE FRONT FROM SHIFTING
SOUTH AND SE AT MORE THAN A CRAWL. PRESENTLY IT LOOKS LIKE WE WILL
REMAIN IN THE WARM SECTOR SOUTH OF THE FRONT THROUGH THE MIDDLE OF
THE WEEK...AWAITING THE FORMATION OF ONE LAST WAVE THAT CLOSES INTO
A LOW OFF THE NC COAST LATE WEDNESDAY OR WEDNESDAY NIGHT. THERE IS
AMPLE INSTABILITY AND MOISTURE TO PRODUCE AT LEAST SCATTERED
CONVECTION. THERMODYNAMICS ARE NOT OVERLY IMPRESSIVE IN REGARDS TO
SEVERE WEATHER...BUT AT THIS TIME OF YEAR THERE IS ALWAYS AT
LEAST AN ISOLATED RISK SHOULD ANY BOUNDARY INTERACTIONS RESULT IN
STRONGER UPDRAFTS. COMPRESSIONAL HEATING IN ADVANCE OF THE COLD
FRONT FRONT...AIDED BY A DEEP WESTERLY FLOW OFF THE APPALACHIANS
WILL ALLOW FOR MANY LOCATIONS TO PEAK AT OR ABOVE 90 EACH AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WITH THE CENTER OF UPPER LEVEL RIDGING REMAINING WELL WEST OF THE
REGION THROUGH THE PERIOD...THE PATTERN ALOFT WILL BE SOMEWHAT ILL
DEFINED AND PROGRESSIVE INTO AT LEAST LATE WEEK. THUS EXPECT
UNSETTLED CONDITIONS TO PERSIST INTO THE EXTENDED FORECAST
PERIOD...WITH FORECAST DETAILS QUITE UNCERTAIN DUE TO MODEL
INCONSISTENCIES. THE LINGERING FRONT OVER OR NEAR THE FORECAST
AREA...WHEN COMBINED WITH WEAK SHORTWAVE ENERGY EMBEDDED WITHIN
UPPER TROUGHING...WILL MAINTAIN DEEP MOISTURE AND CONVERGENCE TO
SUPPORT THUNDERSTORM CHANCES EACH DAY. MEDIUM RANGE MODELS DO
SUGGEST THAT THE SURFACE PATTERN WILL EVENTUALLY SETTLE TOWARD HIGH
PRESSURE TO THE NORTH AND A COASTAL TROUGH DEVELOPING ALONG THE
PERSISTENT FRONT TO THE SOUTH AND EAST. HIGH TEMPERATURES WILL VARY
LITTLE EACH AFTERNOON...REACHING THE UPPER 80S TO AROUND 90 DEGREES
AWAY FROM THE LOCALLY COOLER COASTLINE.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
00Z TAFS INDICATE PREVAILING VFR CONDITIONS THROUGH MONDAY. THERE
EXISTS A LOW PROBABILITY FOR MVFR CEILINGS AND/OR VISIBILITIES
DUE TO INCREASING LOW LEVEL MOISTURE LATE TONIGHT INTO MONDAY
MORNING...INSUFFICIENT TO INCLUDE WITHIN TAFS. THEN...A SHORTWAVE
TROUGH WILL PUSH INTO THE REGION MONDAY...AND DEEPENING MOISTURE
WILL POOL OVER THE REGION SUPPORTING AT LEAST SCATTERED
SHOWERS/THUNDERSTORMS. ODDS FAVOR THUNDERSTORMS IMPACTING BOTH
TERMINALS AT SOME POINT MONDAY...BUT SPECIFIC TIMING REMAINS
IMPOSSIBLE TO PIN DOWN. CONSERVATIVELY INCLUDED PROB30 GROUPS FOR
THUNDERSTORMS 16-22Z AT KCHS AND 18-24Z AT KSAV...BUT A
SHOWER/THUNDERSTORM COULD OCCUR OUTSIDE OF THESE TIME WINDOWS.
ALSO...FLIGHT RESTRICTIONS WILL OCCUR WITHIN AND CLOSE TO
SHOWERS/THUNDERSTORMS...BUT MAGNITUDE/PERSISTENCE OF ANY SUB-VFR
CONDITIONS CANNOT BE FORECAST WITH ANY CONFIDENCE.
EXTENDED AVIATION...VFR CONDITIONS COULD PERIODICALLY GIVE WAY TO
FLIGHT RESTRICTIONS MONDAY NIGHT THROUGH THURSDAY IN ASSOCIATION
WITH SCATTERED TO NUMEROUS SHRA/TSRA.
&&
.MARINE...
OVERNIGHT...S/SE ACROSS GA WATERS AND S/SW WINDS ACROSS SC WATERS
WILL AVERAGE 10-14 KT...ACCOMPANIED BY 2-3 FT SEAS.
MONDAY AND MONDAY NIGHT...THE LOCAL DOMAIN WILL BE PLACED WITHIN THE
WEST AND NW PORTION OF THE SUB-TROPICAL ATLANTIC RIDGE MONDAY THAT
GRADUALLY GIVES WAY TO A WEAK WARM FRONT OR SURFACE TROUGH THAT
PROGRESSES THROUGH MONDAY NIGHT. WHILE THERE WILL BE SOME INCREASE
IN WINDS WITH THE SEA BREEZE CIRCULATION MONDAY AFTERNOON AND WITH
NOCTURNAL LOW LEVEL JETTING MONDAY NIGHT...SOUTH AND SW WINDS WILL
GENERALLY HOLD UNDER 15-17 KT. SEAS AROUND 2-3 FEET MONDAY WILL RISE
ABOUT ANOTHER FOOT MONDAY NIGHT. ISOLATED TO SCATTERED CONVECTION
WILL FINALLY MAKE A RETURN TO THE COASTAL WATERS DURING THIS TIME.
TUESDAY THROUGH WEDNESDAY...THE QUASI-WARM FRONT OR SURFACE TROUGH
WILL LIFT NORTH OF THE MARINE COMMUNITY EARLY IN THE PERIOD...WHILE
WE FIND THE ATLANTIC RIDGE SUBDUED TO THE SOUTH. MEANWHILE...AN
UPSTREAM COLD FRONT WILL RELUCTANTLY MAKE A SE PUSH TOWARD THE
WATERS TUESDAY NIGHT AND WEDNESDAY. STILL TOO MUCH UNCERTAINTY AS TO
HOW FAR THE FRONT WILL BE ABLE TO PENETRATE...AS THE OCEANIC RIDGE
TO THE SOUTH AND SE ATTEMPTS TO HOLD FIRM. WE DO FEEL CONFIDENT THAT
WINDS AND SEAS WILL ASCEND TUESDAY AND TUESDAY NIGHT...WITH A
TIGHTENING OF THE PRESSURE GRADIENT BETWEEN THE UPSTREAM COLD FRONT
AND THE ATLANTIC HIGH. EVEN SO...ODDS AT THIS STAGE ARE AGAINST ANY
SMALL CRAFT ADVISORY CONDITIONS. WIND AND SEA CONDITIONS WILL THEN
BE DETERMINED BY WHERE THE FRONT ALIGNS ITSELF ON WEDNESDAY...BUT NO
MATTER WHERE IT IS LOCATED...ADVISORY HEADLINES ARE NOT ANTICIPATED.
MARINERS ARE ADVISED THAT AT LEAST SCATTERED CONVECTION WILL
OCCUR...AND WE/LL MAINTAIN A WEATHER WATCH FOR THE POSSIBLE
ORGANIZATION OF STRONGER STORMS MOVING OFF THE COAST IN ADVANCE OF
THE COLD FRONT.
THURSDAY THROUGH FRIDAY...THE FRONT LOOKS TO BECOME MORE DIFFUSE
NEAR OR JUST SE OF THE LOCAL WATERS...AS HIGH PRESSURE BUILDS OVER
NEW ENGLAND AND THE MID ATLANTIC REGION. WINDS AND SEAS WILL BE WELL
BELOW ANY CRITERIA FOR SMALL CRAFT ADVISORIES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...SPR
SHORT TERM...33
LONG TERM...WMS
AVIATION...SPR
MARINE...33/SPR
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